# Keeping Water Sweet



## paul323 (Mar 13, 2010)

Hi folks,

My new boat has two 19gallon water tanks. I was wondering - what do you do to keep the water sweet? I know some recommend adding chlorine/bleach (very diluted), and interested in advice before they go green....

I did search the forums - sure I saw a thread somewhere - but with no success....


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## DwayneSpeer (Oct 12, 2003)

*filter*

Add a water filter and drinking water tap. Use unfiltered water for washing, etc. Adding bleach once a season just prior to use or when putting away for the winter is a method to help assure the tanks are clean, not sweeten the water for drinking. With the bleach you need to let stand a few days and then flush out completely.


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## CaptainForce (Jan 1, 2006)

.......or using it works. If you "turn it over" at a regular rate it will stay good. Take care and joy, aythya crew


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## Omatako (Sep 14, 2003)

If your tanks are dark (not white plastic), the water should stay good for a long time without going bad. Light makes water deteriorate. We can and have carried 1000 litres of water which has lasted several months without any treatment and the water was still good at the end. 

I guess though that it depends on the start point - how good the water was when it was put in.

But there are folks that filter the heck out of water and that works for them too.


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## sailingdog (Mar 19, 2006)

One thing that will help is putting a filter on each of the vent lines to the tanks. A majority of contaminants come in via the vent lines-mold spores, pollen, dust, etc., and adding a filter to the vent line eliminates most of this.

I'd also point out that if you are shock treating your water tanks, you really don't want or need to let the bleach sit in the tanks a few days as previously suggested. That is really unnecessary and really a bad idea if you have aluminum water tanks.

From Peggie Hall's instructions:



> l Fill the water tank with a solution of 3/4 dl. of household bleach per 10 litre tank capacity.
> Turn on every faucet on the boat (including a deck wash if you have one).
> Allow the water to run until what's coming out smells strongly of bleach.
> Turn off the faucets, but leave system pressurised so the solution remains in the lines.
> ...


She also points out the necessity of keeping the water flowing through the system by using it regularly and frequently.


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## paul323 (Mar 13, 2010)

Hmmm...my tanks are plastic, but normally away from light - I guess the best answer is, like everything else in a boat, if used regularly it should be fine....

Vent lines - should have thought of that - good tip.

Dang - should have thought of Peggie's advice! I'll have to get her book, as her advice always seems sound. 

Thanks!


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## jarcher (Jul 29, 2008)

A well timed thread for me. I mostly just race my boat, and as such never fill the water tank. For drinking we bring bottled water and I don't want the extra weight. 

However, my wife today complained that there is never any water on the boat for washing. So my project for this week is cleaning out the water tank. I'll probably just replace the lines, since they are short and came with the boat. 

What got my attention is when SD mentioned "vents." I don't believe my tank has any, which is probably not possible, since when water comes out I guess air has to get in somehow. If I have to add them, what do I add? Are they just lines from the top of the tank out? Do they have any special fittings, like a one way valve or anything?


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## sailingdog (Mar 19, 2006)

A vent line usually comes from the highest point on the tank and usually has a through-hull fitting that has a screen on it to prevent insects from nesting in the line.


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## ffiill (Jul 15, 2010)

Will have to do mine-low turn over and 80 gallons!-


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## SlowButSteady (Feb 17, 2010)

Omatako said:


> ... Light makes water deteriorate...


Huh? Into hydrogen and oxygen? I don't think so. Light will allow growth to form in you tank, but the water doesn't "deteriorate".

I add a cap-full of bleach every time I fill my water tank (20 gal) to keep the biological activity at bay (it's a white HDPE tank, but it's in a dark locker). That keeps the water potable, albeit with a slight chlorine taste right after aI fill the tank. However, I normally only use the tank water for washing. For drinking/cooking I buy those little 2.5 gal carboys of water at the grocery story, and keep a stash of San Pellegrino in the ice chest.


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## hellosailor (Apr 11, 2006)

Since venting a tank brings in the same outside air AND all the critters that make sourdough bread and beer (yeasts!) and all that stuff can and will grow in the tank...maybe it also makes sense to put a charcoal filter on the water tank vent, to inhibit some of the critter entry?


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## sailingdog (Mar 19, 2006)

A particulates filter is more important than a charcoal filter IMHO.


hellosailor said:


> Since venting a tank brings in the same outside air AND all the critters that make sourdough bread and beer (yeasts!) and all that stuff can and will grow in the tank...maybe it also makes sense to put a charcoal filter on the water tank vent, to inhibit some of the critter entry?


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## Bene505 (Jul 31, 2008)

I've used a screw-on kitchen water filter with good success. It's the kind that you twist it one way for washing and the other way for fintered water. IIRC, it was about $50 and lasted the summer and then a few months longer at home in the fall.

Regards,
Brad


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## rmeador (Jan 16, 2010)

Does some company make filters for boat water tank vents? Where might you find such a thing? It makes sense that this would be a primary source of contaminants, and is possibly answers a question that's been circulating in my head for a while now: why do boat/RV water tanks go "bad" and need to be shock cleaned periodically, but the pipes in your house do not?


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## sailingdog (Mar 19, 2006)

Some reasons that water systems in houses usually don't go bad is that the pipes are usually COPPER, and unless the house isn't occupied, the water flow through the water system is usually quite good. Finally, there isn't really a storage tank on a home water system, and there is no vent line into the water tank, like there is on a boat's water system-so the possibility of contamination is much lower.



rmeador said:


> Does some company make filters for boat water tank vents? Where might you find such a thing? It makes sense that this would be a primary source of contaminants, and is possibly answers a question that's been circulating in my head for a while now: why do boat/RV water tanks go "bad" and need to be shock cleaned periodically, but the pipes in your house do not?


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## jarcher (Jul 29, 2008)

Thanks everyone, I guess I'll be taking my water system apart soon :-(


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## scraph (Oct 19, 2009)

I ... don't understand why ... you can't just chlorinate your drinking water. There are "freshwater fresheners" sold at West Marine that are essentially diluted chlorine bleach (diluted to ease dosing).

According to the EPA (http://www.epa.gov/ogwdw000/faq/emerg.html), fresh water can be disinfected by adding 5.25% laundry chlorine bleach (no soaps or scents) at a ratio of 8 drops per gallon (8 drops is also 1/8 teaspoon) ... so for 20 gallons add 2.5 teaspoons.

This is not shock treatment. This is perfectly acceptable and healthy chlorination of drinking water for storage and consumption that is done daily ... and it works great.


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## knothead (Apr 9, 2003)

For drinking water, a good filter such as the Berkey is the way to go. Especially in an emergency or when you aren't sure about the quality of the water. 
Berkey water filter
For other on board uses I would think a little bleach and an inline charcoal filter would be fine.

I haven't drank a drop of water in the last six months in my home that hasn't fallen on my roof. I have the "Big Berkey" but only have two filters in it as I'm only purifying filtered and settled rain water.

I like the security of knowing that in an emergency, I could drink the pond water or water from pool or whatever. 
I also like the fact that I'm no longer ingesting fluoride or chlorine.


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## knothead (Apr 9, 2003)

scraph said:


> I ... don't understand why ... you can't just chlorinate your drinking water. There are "freshwater fresheners" sold at West Marine that are essentially diluted chlorine bleach (diluted to ease dosing).
> 
> According to the EPA (http://www.epa.gov/ogwdw000/faq/emerg.html), fresh water can be disinfected by adding 5.25% laundry chlorine bleach (no soaps or scents) at a ratio of 8 drops per gallon (8 drops is also 1/8 teaspoon) ... so for 20 gallons add 2.5 teaspoons.
> 
> This is not shock treatment. This is perfectly acceptable and healthy chlorination of drinking water for storage and consumption that is done daily ... and it works great.


Chlorine is great for killing bacteria but do you really want to drink it? I wouldn't hesitate to put it into my tanks and drink it in an emergency, but it's been pretty well established that the stuff isn't good for you.
Filter your drinking water.

*Chlorine is a deadly man made poison.*

Healthy Water for Healthy Skin: Chlorine is a deadly man made poison.


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## hellosailor (Apr 11, 2006)

"Chlorine is great for killing bacteria but do you really want to drink it?"
That's why you don't chug from the jug. Used in moderation, and allowed to stand and break down--as it does--it shouldn't be a problem or a poison. It is in many municipal water systems and the key word is moderation.

But chlorinated water isn't what anyone would call "sweet" water. At best it will be sanitized water. Sweet water has, well, that appealing taste of fresh rainwater or a fresh stream. (Which is chock full of giardia and other bad things no matter how good it tastes.)

Chlorinate it, or use iodine. Or a UV-C light source. Let it oxidize out, charcoal filter it, shake it up good to aerate it, it'll be just fine.

Or like many sailors, use the tank water for washing, and keep your favorite bottled water on board for drinking.

Chlorine is a deadly poison. So is water itself--in quantity and without electrolytes. So is cyanide--but we consume that in apple seeds and other foods without batting an eyelash.

Moderation.


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## sailingdog (Mar 19, 2006)

Not a good idea on some many levels. First, as others have pointed out, the stuff is pretty nasty-and won't leave you with sweet water. Second, it tends to damage a lot of the things in the fresh water system. It is bad for rubber and plastic parts that are in many of the pumps and such. It isn't good for the hoses. If you have an aluminum tank, constantly adding bleach will KILL THE TANK.



scraph said:


> I ... don't understand why ... you can't just chlorinate your drinking water. There are "freshwater fresheners" sold at West Marine that are essentially diluted chlorine bleach (diluted to ease dosing).
> 
> According to the EPA (http://www.epa.gov/ogwdw000/faq/emerg.html), fresh water can be disinfected by adding 5.25% laundry chlorine bleach (no soaps or scents) at a ratio of 8 drops per gallon (8 drops is also 1/8 teaspoon) ... so for 20 gallons add 2.5 teaspoons.
> 
> This is not shock treatment. This is perfectly acceptable and healthy chlorination of drinking water for storage and consumption that is done daily ... and it works great.


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## scraph (Oct 19, 2009)

First, the OP is asking to store the water and keep it tasting sweet. I have no idea what sweet water is but I'm just assuming that water that tastes like algae is not it.

On the half-educated scare tactics thrown about on the dangers of drinking chlorinated water ... lets actually discuss the truth of the matter instead of some South Park-esque statement of "chlorine is bad, mmmkay".

Chlorine in drinking water, itself, has *not* been found to pose a direct health risk. The health risks others may have been referring to (unless the limit of their understanding really is "chlorine is bad") is related to a byproduct of chlorine treatment, THMs. Trihalomethanes (including, chiefly, chloroform) have been linked with increased incidence of rectal and colon cancers, among other scary sounding cancers. THMs are produced through chlorines interaction with organic matter in drinking water (ie twigs and leaves). This is a relevant point for chlorinated municipal water because these water supplies do contain such organic matter in water mains, etc.

Now here's the rub ... people mention carbon filtering as all you really need. We'll discuss that now. Carbon filters remove particulate matter, organic matter (remember those twigs and leaves), as well as ... THMs. Carbon filters do not remove *microbes*, sodium, nitrates, fluoride, and hardness. Also, only specific carbon filters will remove lead and other heavy metals. Microbes are why you don't drink the water in foreign countries, they're why you bring iodine tablets on a survival trip, and they're why third-world countries suffer from so many waterborne illnesses. Microbes are also what makes stored water go bad.

Chlorine is one of the most effective means to disinfect water (second only to boiling and distillation). Chlorinated drinking water for the rest of the world (and apparently not the new age hippies) has been associated with vastly improved health conditions.

So, here's the deal. You filter the water (to removed organic matter and prevent its negative interaction with chlorine), chlorinate the water (to disinfect it and allow prolonged storage), and then you can filter it at the tap (to make extra certain you remove those nasty THMs).

I say again ... chlorination of filtered water ... or filtration of chlorinated water does not pose a health risk.

As far as the effects of chlorination on the components of the water system ... sure. I don't chlorinate the water when I'm cycling through the tank fast enough ... but he asked to keep _stagnant_ water fresh. Besides, chlorinating the water at drinking levels only when you plan on keeping the water in the tank is better than shocking the tank when you allow unchlorinated water to go bad.

Carbon filtering will not disinfect water and will not prevent the growth of bacteria in stored water. Some of you need to read past the headline of "chlorine in drinking water kills children and small animals" because there is actual science ... and information ... behind the subject.


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## RichH (Jul 10, 2000)

Hopefully this post will alleviate/stop all the myths and mysticisms about 'boat water tanks' ... as they are quite important if you drink or wash with this stuff.

As a stunning illustration of the what can go WRONG, take a plastic or glass water jug, scrupulously clean it, fill it with tap water, and put it away in a warm place for a few weeks/months. Notice when you open the top that there is a slimy film on the surfaces that the water touched - these are massive bacteria colonies (calcyx) of which some will be quite harmful. Notice the smell of the water, these are from the decomposition of the bacteria colonies, molds and mildews that began to grow, then died and decayed on the surfaces .... and this was a scrupulously clean container. 
OK with the same now fouled contained go to West Marine and buy some 'tank deodorant', or maybe some lemon juice, or someother common remedy for 'sweet water' .... maybe you want to 'run it through' a charcoal filter but odds are knowing that water tastes BAD either because there is a massive biological 'soup' now growing in it or the 'plastic' of the container is now leaching chemical fragments into the 'water' .... you really put yourself, etgc. at great risk applying myths and mysticisms to a FOULED water. Knowing that the chief cause of 'funky water' is dead and dying bacteria, fungals, etc. or chemical fragments of the tanks/system .... I dont think you are going to 'filter' with charcoal and then actually drink this 'sludge'. 

Municipal water systems try to keep chlorine activity to 1 parts per million to keep the microbiological soup from propagating in their distribution lines. Occasionally, and after 'working' on the lines, especially if the lines have been opened up to the atmosphere, they will 'shock' the system with 10-20 parts per million of chlorine, then flush the system and maintain it at about 1 part per million of chlorine. There are many biological species that are chlorine resistant ... and in those systems where these are present mega-$$$ are being spent on quite expensive filtration systems are installed. Well water can contain 'wild strain' bacteria that live down deep in the earth .... hard to assay but can be quite a problem. 

The problem with water tanks in boats are they are. just like the water jug you put away for several/many weeks, are STAGNANT systems and are prime breeding grounds for bacteria, etc., the warmer the tank/water the greater the 'growth'. If your tank has a VENT, everytime you 'draw down' the water from the tank, atmosphere spores of bacteria, mold, fungus, mildew get sucked down that vent into the tank .... at a rate of about 100,000 'particles' per cubic FOOT of air sucked in. The BLACK **** you see growing inside water tanks can be very BAD (for human tissue) mildews such as stochybatris autra, aspergillis, etc. ; the slimes can be forms of pseudomonas (brevundamonas) common 'nasties' that are common to STAGNANT water systems. 

Carbon - removes 'taste', but also adsorbs chlorine from the water and can become a nutrient source for the bacteria, etc. already IN the tank. I repeat you need the Chlorine and the 'charcoal' REMOVES it. 

MAINTAINING A 'CLEAN' WATER SYSTEM
1. PHYSICALLY CLEAN OUT the TANK. Scrub out all slimes, all the 'colored' **** - just like you do with your dishes, and glassware. FORGET about shock sanitizing without FIRST 'mechanical scrubbing' as shock sanitizing will only kill the upper 'surface layers' of bacteria colonies. The shock sanitizing 'recipies' you see touted to shock boat water tanks, etc. is for THE COMMISSIONING OF ****NEW**** systems, systems NOT PREVIOUSLY FOULED. 

2. Once the system has been meticulously mechanically scrubbed and flushed. Then 10 parts per million of Chlorine (50 ounces of laundry grade Clorox (5%) per 100 gallons, let soak for 1-4 hours to SHOCK SANITIZE, then FLUSH out completely with clean water. REMOVE AND REPLACE any hose that has turned 'dark' or looks 'funky' .... including the VENT hose. Wait until you see that hidden vent hose ---- its going to make you 'power-puke' when you actually SEE it. 
Hydrogen Peroxide, anyone? Dont friggin bother as the concentration of 'drugstore' hydrogen peroxide would require that you fill the ENTIRE system with 'undiluted' drugstore hydrogen peroxide to even begin to kill bacteria, etc. ---- quite expensive. Commercial / industrial concentrations of hydrogen peroxide are EXTREMELY DANGEROUS to use .... dont even think about using 'non-drustrore' potency H202. 

3. The 'maintenance' dosage of water is 1 ppmw chlorine (5 oz. of 'clorox' per 100 gallons). Municipal water is already treated with chlorine, so you probably dont have to add chlorine if its supplied from a MUNICIPAL SOURCE. Well water NEEDS to have chlorine added to retard the biological GROWTH (dosage above). 

3a. The BEST amount of chlorine/clorox to add is 'just enough' in the water so that your WIFE can 'just barely' smell the acrid aroma of the chlorine coming out of a spiggot'. That means that there is FREE chlorine in the water, ready and able to oxidize any growing cells that may be in there.

4. Charcoal filters .... if you NEED them, you HAVE a funky, contaminated, system OR a system that is emitting CHEMICALS from the 'plastics' in the system. 
Charcoal filters should be on the HOSE*** that you use fill the tank with .... run the charging water AS SLOW AS POSSIBLE through the charcoal filter as you fill the tank as it takes TIME to do the 'adsorbing'. Once you are finished filling the tank with the dock hose, drain the water out of the charcoal filter and store it 'dry'. 
If the tank is clean and 'sanitary', has 1 ppmw of free chlorine, it should remain 'good' for a long time. If it begins to 'taste' like chemicals, its probably a plastic in the system that IS NOT RATED FOR USE WITH POTABLE WATER, is emitting 'monomers' and other 'chemical fragments' --- find it and REMOVE IT from the system. 
Fiberglass tanks are suicide ... they emit styrene and other fragments. Epoxy tanks emit 'amines'. Only FRG tanks that are made from resins that are rated/approved by the NSF/FDA for *POTABLE WATER* can be used for 'potable' water.

Dock HOSE**** - an FDA/NSF 'rated for POTABLE WATER' hose, not a plain vanilla cheapo garden hose that has tremendous VINYL monomer emissions. 

5. The 'charging hose' (with the carbon filter already on it) should be filtered to 1,0µM (100% or 'absolute') to exclude chlorine resistant species. Such filters will/can also be be 'rated': for 99.9% removal of oocysts or cysts, etc. The is ESPECIALLY important for municipal water systems that get their water from 'surface sources' such as rivers, lakes and reservoirs and DO NOT guarantee the exclusion of: Crypotosporidium and Giardia Lamblia - chlorine resistant species. 

6. Put a 'filter' on the tank vent. The simplest and yet effective is to simply take a fist-sized wad of 'bandage cotton' put it over the end of the CLEAN vent hose opening, and cover loosely with 'bandage gauze', keep DRY and change yearly. 
Commmercial 'capsule' filters of hydrophobic PTFE @ 0,2µM 'absolute' are available from major pharma filter corporations such as Millipore, Pall, GE/Cuno, Parker Advanced Filtration, Meissner, etc. price is about $75 - 100 each. 

You cant have a sanitized water system that isnt a CLEANED system, especially since 'boat' water systems are STAGNANT. 

Hope this helps.


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## scraph (Oct 19, 2009)

RichH said:


> Hopefully this post will alleviate/stop all the myths and mysticisms about 'boat water tanks' ... as they are quite important if you drink or wash with this stuff.


Oh thank the Lord  Someone who isn't trying to claim that chlorinated water (one of the greatest benefits to overall health in developing nations) is actually one of the worst (to Americans, who believe that everything causes cancer, and think we just naturally don't get dysentery or malaria because of our air conditioned homes and hybrid automobiles).

Thanks for pointing out that freshwater systems on a boat are stagnant water ... similar to a muddy puddle in Africa. Great post. Renewed my faith in the forum.


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## RichH (Jul 10, 2000)

Waterborne diseases are the LEADING cause of premature death in the 3rd world. 
The USA greatest incremental increase in lifespan (early 1900s) was due to the 'sanitarians' cleaning up the water systems and by adding chlorine. 

Complaining about chlorine in water at this point in time is just 'lawyer talk' to increase the future probability of gaining a FAT contingency fee .... same is happening with a lot/most of 'chemicals', etc. 
..... the 'duping' of the country to set up 'public opinion' (of potential future juries) simply for easy future profit - a stunning legacy of what happens to a country when there is 1 'lawyer' per 250 citizens.


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## SlowButSteady (Feb 17, 2010)

1) If adding a little bleach to my boat's water system is so bad for the plastic components, why can a bottle of _full strength_ bleach sit on the shelf for months or years w/o disintegrating?

2) If chlorine is so dangerous for us, how did I survive all those summers as a kid at the wildly over-chlorinated community pool? I know I must have ingested some water during those endless games of Marco-Polo.

3) Although it may not be feasible for those sailing off-shore or to other countries, for most of us (90+%, perhaps) the easiest way around most of this (as I said earlier) is just to get some bottled water, and/or 2.5 gal carboys, for all your cooking and drinking purposes. Or, just get used to a slight chlorine taste to your water (it ain't gonna kill you).


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## knothead (Apr 9, 2003)

scraph said:


> First, the OP is asking to store the water and keep it tasting sweet. I have no idea what sweet water is but I'm just assuming that water that tastes like algae is not it.
> 
> On the half-educated scare tactics thrown about on the dangers of drinking chlorinated water ... lets actually discuss the truth of the matter instead of some South Park-esque statement of "chlorine is bad, mmmkay".
> 
> ...


I guess I'm the half educated one you are referring to. No problem. You want to drink chlorine, flouride? Go ahead. Me, I would rather drink pure water. 
But then I'm only half educated. 
The filter I recommended does in fact remove microbes.

*The Imperial Berkey countertop water filter removes harmful bacteria, microbes, and unwanted chemicals* from water to leave you with a pure drinking water.

Imperial Berkey Large Filter | Family size | removes bacteria chlorine

_More studies link fluoride to bone and other cancers but are downplayed or
ignored by government officials.(4)(5)

Bone defects similar to bone cancer were detected in fluoridated Newburgh, NY__
children as early as 1955._

Another Study Links Fluoride to Bone Cancer | Reuters

_"I would drink chlorinated water only if the alternative was no water at all."---Paul A. Stitt
 "Hydrogen peroxide (H2O2) destroys infectious organisms and impurities in water 4,000 times better than_ _ chlorine."---Joseph G. Hattersley
_

Chlorinated water

These guys are probably only half educated too. :laugher​


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## scraph (Oct 19, 2009)

knothead said:


> I guess I'm the half educated one you are referring to. No problem. You want to drink chlorine, flouride? Go ahead. Me, I would rather drink pure water.
> But then I'm only half educated.
> The filter I recommended does in fact remove microbes.
> 
> ...


The question is not of _drinking_ chlorinated water. If you have a problem with drinking chlorinated water then filter it. All that information discusses drinking it, unfiltered. The question is of _storing_ stagnant water. It should be chlorinated to keep it disinfected. Residual chlorine is what keeps it clean. Putting clean water into a tank, as explained by RichH, does not keep it clean when it is stored.

While you're insistent with providing the very same information with no more explanation ... my posting *directly* discussed the information and misunderstandings of the information you just posted, again.

Very well, you found a good filter. I recommended filter use too... in conjunction with chlorinated water in storage.

Here's the point ... chlorine treated water, while it may cause random things that took 50+ years to uncover through science, alleviated the leading causes of death in third world countries immediatelly. If you're going to keep the water stagnant in the tank without disinfecting the water ... it's going to grow nasty smelling, likely fatal colonies of bacteria in it. The problem here is not of chlorination. The problem is ... keeping stagnant water in the freshwater tank. It is a tall order and, while maybe not ideal, chlorination will allow that water to be stored. 
You can filter it on the way in to the tank (which your mentioned filter will serve for admirably) but any amount of bacteria which enters through the tank vent or that is found anywhere in the system will still grow in your purified water during storage and it will still turn bad.* Filtration *may clean the water ... but it *doesn't keep it clean *during storage. It is the *residual chlorine* level that *keeps* stored water disinfected. You can filter it on the way out of the tank (immediatelly before drinking) and allow it to do whatever it will in the tank ... but then you'd still have to wash your dishes and shower in bad water.

Chlorinate water for stagnant storage. If drinking chlorinated water really bothers you all that much then, by all means, find a filter which removes the chlorine. However, simply putting pure water into the tank *doesn't keep it clean* and it is reckless of you to claim that it will.


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## paul323 (Mar 13, 2010)

I love these forums....especially when we get a constructive dialogue (albeit with some differing opinions!)

As the OP I apologise for the ambiguity in my original post. By "sweet" I did indeed mean reduce the likelihood of microbial (primarily algal and bacterial) contamination and growth in the water tanks of an occasionally used (1-2 times a week) sailboat. As previously discussed, infrequently used tap filters have drawbacks, and I was wondering about other options...so anyway I learned a heck of a lot from you folks. Thank you.


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## rmeador (Jan 16, 2010)

RichH, what is the definition of "stagnant" water? If you're living aboard and refill your tank every two weeks, is that stagnant? What about once a week?

Also, if the municipal water supply has chlorine in it, are you still advocating adding extra chlorine to the tank (assuming I fill the tank without a filter)? Does it make a difference for the situation I outlined above vs someone who uses the boat once a week?


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## knothead (Apr 9, 2003)

scraph said:


> The question is not of _drinking_ chlorinated water. If you have a problem with drinking chlorinated water then filter it. All that information discusses drinking it, unfiltered. The question is of _storing_ stagnant water. It should be chlorinated to keep it disinfected. Residual chlorine is what keeps it clean. Putting clean water into a tank, as explained by RichH, does not keep it clean when it is stored.
> 
> _I agree and never claimed otherwise_
> 
> ...


_Please respond to what I actually say, not to what you think I mean. You don't know anything about me and it's rather presumptuous of you to act like you do. _


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## scraph (Oct 19, 2009)

I wrote that Activated Carbon filters do not remove microbes. That is true, they do not. Your Berkey filters are unique in what they claim to filter. They must not be activated carbon ... and AC filters are what was being recommended earlier in this posting. I scoured their site ... they make no mention as to the filtration technology that they use. They claim to remove 100% of microbes ... and everything else that you wouldn't want in water ... but also make certain to mention that beneficial minerials pass through unhindered. I'd really prefer any amount of supporting evidence from them with all of these claims ... meanwhile, their website seems to contain only marketing claims, not scientific information.

I'm sorry your feelings were hurt ... but I was responding to the misinformation and half-truths being propagated in this thread, not your feelings. Back on topic now...


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## scraph (Oct 19, 2009)

rmeador said:


> RichH, what is the definition of "stagnant" water? If you're living aboard and refill your tank every two weeks, is that stagnant? What about once a week?
> 
> Also, if the municipal water supply has chlorine in it, are you still advocating adding extra chlorine to the tank (assuming I fill the tank without a filter)? Does it make a difference for the situation I outlined above vs someone who uses the boat once a week?


I'll take this one, if that's alright.

"Stagnant water" is defined as water which does not flow or circulate. Water stored in a tank is, by definition, stagnant. The time stored is not necessary to define it as stagnant. Of course, the longer it is stored then the worse the results of the stagnation. It is stagnant just because it is in the tank. Whether or not it has "stagnated" is a question of whether it stays fresh for as long as you store it. (but this is just semantics)

Chlorine is a gas at room temperature and is dissolvable in water. The chlorine smell of chlorinated water is, in fact, chlorine leaving the water. If the water in your tank, or out of your tap, has a slight but distinguishable smell of chlorine (with the levels already present from municipal water supply) then you likely don't need to add anymore. If not, you likely do want to add more.

You can, of course, give it a trial. Fill the municipal water into the tank and see whether it will keep itself fresh for however long you require. If not, then you want to clean the system (as RichH outlined) and begin chlorinating the water in the tank.

To the OP, I'm very glad you could glean the information you desired from this thread! Glad we could all help.


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## rmeador (Jan 16, 2010)

scraph, thanks for the info. Since I last posted, I've done a bunch of research on chlorination online. I've discovered that the local water supplier uses chloramine, not chlorine, to treat the water. This apparently lasts much longer and doesn't give a chlorine smell, so I presume it would be OK in a tank for the lengths of time I'm talking about (I'd appreciate confirmation of this). I wondered why the water here in Boston was drinkable straight from the tap, and I guess this is why. Most of the other places I have lived have such awful chlorine smell/taste in the water that it is undrinkable unless filtered.

It also appears that bleach comes in two varieties, chlorine and sodium hypochlorite. I've only ever seen the latter in stores, and I always assumed when people spoke of "chlorine" bleach this is what they were talking about, but now I think they're actually distinct. Can both be used for tank treatment, and if so, should different amounts of them be used?


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## knothead (Apr 9, 2003)

scraph said:


> I'd really prefer any amount of supporting evidence from them with all of these claims ... meanwhile, their website seems to contain only marketing claims, not scientific information.


University of Arizona
Deptartment of Soil, Water and Environmental Sciences

Evaluation of Three Black Berkey Filter Formulation Purification Units

http://www.green-trust.org/diyrainwater/berkey-lab-test-results.pdf

These guys are at least 3/4 educated.


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## JimMcGee (Jun 23, 2005)

I think the posts by Scraph and RichH make a lot of sense and should be condensed and made sticky under gear & maintenance. 

Jim


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## scraph (Oct 19, 2009)

knothead said:


> University of Arizona
> Deptartment of Soil, Water and Environmental Sciences
> 
> Evaluation of Three Black Berkey Filter Formulation Purification Units
> ...


First ... that file contained 3 (with partial data in some cases) seperate lab tests. Only the first (the one with only results and synopsis, and no experimental data) was performed by the Univ. of Arizona. The second lab result was by "Spectrum Labs Inc". The third lab result was from a department of Louisiana State University. But I'm certain you actually read through the reference you posted...

Those results look good as far as C.parvum and E.coli ... effective. One issue I see though is that the tests were conducted at a rate of only 200ml/min (and under negative pressure ... so, pump on the outlet, not the inlet). So ... this filter has not been proven effective at removing microbes at 2gpm ... or any other reasonable flow rate required to fill a freshwater tank. Another problem with that test ... they had only, in the end, passed <2 gal of water through the filter. How well does it filter at 20gal? The other tests indicate not nearly as well as the claims...

The results show that it is effective, and remains effective at 100gal filtered, at removing Chlorine. However, this lab result makes no mention of the filtration flow rate (shall I assume it is 200ml/min?) It did take them 5 days to get up to 85gal...

As far as Lead filtering... the Lead content of the effluent sample is initially <0.001 but by 15gal it is now measurable. At only 25 gal, it is now just 96.4% efficient at removing lead. I wonder how effective it will be at 30, 40, 100gal when it was measured 99.4% efficient at 20 gal (that's a loss of 3% effectiveness after only 5 more gal filtered).

With Chloroform (their surrogate for THMs), it was immeasurable in effluent at 15gal filtered. At 20 gal, 99.88%. At 25 gal, 98.5% (the amount of Chloform in effluent after 25gal went up by an order of magnitude over the 20gal results).

The results you provide, while showing effectiveness as a filter, also clearly show a marked loss in filtration efficiency of all things measured (except Chlorine itself) at only 20 gal filter usage. None of the studies measured these things (or, maybe, showed the results) past 25gal. They, however, did publish results for Chlorine removal up to 100gal. It does strike me as odd that _they stopped measuring Lead and THM removal when it started trending in the wrong direction but freely published Chlorine removal up to 100gal_. Now ... do you want a Chlorine filter? Or a microbial filter?

The final study, measuring removal of the 3 listed microbes, didn't even run more than 10gal through the filter.

The studies provided show that they are effective filters when brand new but it sure looks like they exhaust very quickly ... and they have only been proven to filter effectively at 200ml/min (that would be about 6 hours to fill a 20gal tank...)

I, for one, will not be spending $50 to filter a single 20gal tank worth of water. The results sure don't indicate the filter lives up to their filtration claims past 20gal.

While this filter may be effective for drinking water only ... it certainly does not serve the purpose or address the issues of the OP in keeping stored water fresh. ... and, once again, the results indicate a poor lifetime for a filter (to meet their own magical claims).


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## RichH (Jul 10, 2000)

The technical definition of 'stagnant' is water that is moving at less than about 9 feet per second; such velocity doesnt allow bacteria to 'reproduce' or 'divide'. Can be obtained by careful water distribution design or by continually 'pumping'.


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## RichH (Jul 10, 2000)

knothead said:


> University of Arizona
> Deptartment of Soil, Water and Environmental Sciences
> 
> Evaluation of Three Black Berkey Filter Formulation Purification Units
> ...


Thats a pretty misleading report as 'standard' retention values are in the range of 1X10^10 to 1X10^13 influent particles per sq. cm of filter media .... and it lists specific (specific size) microorganisms not the universally accepted brevundimonas (pseudimonas) diminuta - an ASTM 'standard' test organism. The test doesnt list the surface area of the filter so it leads one to surmise 'salesman talk' or purposeful 'skewing of the numbers'. So what that report really means is that IF the water *only* had E. Coli or that specific oocyst, then these filters 'might' provide a high value of 'protection'. Id say these folks are only 1/2 educated although the 'cyst' retention is acceptable but 'vague'. :hammer


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## scraph (Oct 19, 2009)

rmeador said:


> It also appears that bleach comes in two varieties, chlorine and sodium hypochlorite. I've only ever seen the latter in stores, and I always assumed when people spoke of "chlorine" bleach this is what they were talking about, but now I think they're actually distinct. Can both be used for tank treatment, and if so, should different amounts of them be used?


Good question. I can understand the misunderstanding on this.

Household Chlorine bleach is sodium hypochlorite solution. Sodium hypochlorite is the compound added to water to provide the Chlorine. In water chemistry, the hypochlorite and chlorine establish an equilibrium and both exist in the water. If Chlorine gas were to be dissolved directly into water, this equilbrium would still occur and Hypochlorite would be created. The only difference between these two ways to get a Chlorine solution is that dissolving chlorine gas directly doesn't added Sodium to the solution whereas adding Sodium Hypochlorite does ... in both cases though, you get Chlorine and Hypochlorite. (for comparison, pool chlorine is added by Calcium Hypochlorite).

In summary, Chlorine and Hypochlorite will always coexist in water ... the Sodium is just part of process of deliver the Hypochlorite to the solution.


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## speciald (Mar 27, 2007)

There is a product called Aquabon that "guarantees fresh tasting water" - seems to work; its made for motor homes. I add hydrogen peroxide to my tank, not chlorine as I worry about chlorine in the stainless steel tank and the posibility of chlorine getting to the watermaker membranes that are destroyed by chlorine. All water on my boat is either made by the water maker or passes through a particlate and a carbon filter. We use a Brita filter for drinking water.


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## knothead (Apr 9, 2003)

This will be my last reply to this thread as it seems rather futile. A well respected friend gave me this advice and I think I'll take it to heart. 
"_assume a certain percentage of people are dogmatic in their beliefs and will believe black is white till they die regardless of any evidence, scientific or anecdotal, to the contrary - forget about them._ _The rest will respond in varying degrees depending on their background, some to authority figures, others to testimonies of like-minded people, some to scientific evidence, some only to their own experience_."

Pretty smart guy huh?

The unit that I use is a counter top, gravity fed filter system that I use for drinking water. 
I contacted the representative of the company who answered my questions when I was considering the purchase of the Berkey filter about the doubts you guys have regarding the test results from the UoA and this is his response.

_The Black Berkey Filter was tested with more than 10,000 times the concentration of pathogens per liter than is required by standard testing protocol. It is certified to eliminate pathogenic bacteria to the EPA's "7 Log" purification standard of 99.99999% reduction _
_The Black Berkey purification element formulation was tested by the following State and EPA accredited laboratories: _
_The University of Arizona, _
_Spectrum Labs, _
_The Department of Toxicology and Environmental Science, Louisianna State University _
_I've attached the three lab reports. Let me know if there is a problem opening them._

_You can also find them here at our 911water site - 
Berkey Lab Test Results_

_I lived on a coastal cruiser, a California 48, for 2 years. I haven't done much sailing but am anxious to learn. We had an RO unit on the boat as we were not in fresh water. The Berkey would be a good choice for fresh-water boating. There are other options for purifying the water but the Berkey would leave you with both safe and good tasting water, most of the other options either are not effective at removing the pathogens or not effective at making the water taste and smell good.

Berkey Lab Test Results

_I know this won't convince anyone of anything and I'm not really sure why I am wasting my time, but there it is. 
If you want to drink water that contains chlorine, fluoride, lead or whatever, go ahead. If you want to think I'm stupid for wanting to drink pure water, then go ahead. I gave it my best shot.
I'm done now.


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## scraph (Oct 19, 2009)

You can indirectly call me whatever names you wish. I've read the references you submitted regarding chlorinated water. I've also read the "lab reports" you provided regarding your filter.

Maybe some people don't actually read past the first line ... I do. The lab reports you provided are vague, incomplete, inconclusive, and don't include very much actual data. Also, the actual experimental conditions were not described to any satisfying complexity.

You did provide links and references. If they were actually read with a critical mind one would find they don't prove everything they appear to claim... or you would find that the lab reports you reference *are not complete lab reports*. Pardon me for requiring good information in order to draw conclusions.

This thread is about storing water, not drinking water. Storing water. I still fail to see what your fancy Brita has to do with storing water. I also fail to see what the relevance of health risks associated with consuming chlorinated water has to do with storing chlorinated water ... especially when you filter the water before consumption ...


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## fallard (Nov 30, 2009)

I only use a small amount of bleach at the beginning of the season and then flush the tanks thoroughly. The bleach may kill most of the organisms that made it through the winter in New England, but it doesn't clean the tank and pvc hose of dead organisms. The water on our 21 yr old boat doesn't taste funny and we're comfortable brushing teeth and washing with water from the tanks, but we use plain bottled water (gallon size) for tea, coffee, and food preparation. For our purposes the gallon size is more convenient than the larger carboys.

We are also careful not to put a hose into the fill at a dock away from home. You want to flush the hose nozzle before you fill and hope that someone before you didn't stick it into their pump out fitting to flush their holding tank.

At some point (manana?) I plan to clean out the water tanks and replace the reinforced vinyl hoses.


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## tommays (Sep 9, 2008)

Well

I work to USP 643 and can't make any sense of the test results 

When you have to stress about 500 ppb being junk doing anything in ppm seems so dirty


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## WanderingStar (Nov 12, 2008)

Will I create panic and fear if I tell you all that I add nothing to my water but water? I do use a hardware store filter before the galley pump, at the end of last season it had what looked like (and probably was) clay in it. When I bought the boat I rigorously tested the water in the tanks. It tested safe. since then I fill it from dockside hoses and drink it. It's the same water I drink at home. I do let the hose run a few minutes to clean it out. My tanks and lines are metal, that may help. But I also remember drinking pond water and rain puddles as a kid. And we're only a generation removed from rain barrels.


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## tommays (Sep 9, 2008)

US-B1 Recreational Vehicle / Marine Filtration System 

Features:

* Provides Cleaner, Clearer Water
* Improves the Taste & Smell of your Water
* Minimizes Concerns Regarding Biologically Contaminated Water
* Connects easily to your Existing Faucet for Drinking & Cooking at your Galley Sink
* Saves you on the cost of storing expensive bottled water

Specifications:

* Reduces >95% of Chlorine
* Reduces Sediment, Dirt, Rust, Sand, and Silt down to 0.2 micron
* Reduces Bacteria up to 99.9999%
* Reduces Cysts (Giardia, Cryptosporidium) up to 99.999%
* Reduces Algae and Mold Spores up to 99.9999%
* Patented Carbon Block for Improved Absorption
* Patented Dual-Zone Nylon Membrane Bacteria Barrier
* 2 GPM Flow Rate
* 2000 Gallon Filter Capacity
* 3/8" Connections Sanitary
* Quick Change Design
* Built in Shut off Valve


If your really worried this is not that much money and has real specs


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## Barquito (Dec 5, 2007)

> But I also remember drinking pond water and rain puddles as a kid. And we're only a generation removed from rain barrels.


... and this may be why people who aren't exposed to such things as kids, will have trouble drinking water out of a tank when they are adults. They just don't have the immunity to the things that occur naturally in our world.

Take home message: Feed your kids some dirt.:laugher


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## tommays (Sep 9, 2008)

And dirty drinking water is a leading killer even were they eat plenty of dirt


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## CapnBilll (Sep 9, 2006)

My drinking water taste improved greatly when I took the tank out, a big hassle, but worth it. And cleaned and scrubbed the slime and algea growing on the sides. I used dish soap, and after removing all the obvious, dumped a whole bottle of peroxide, and swished it around while it bubbled the remaining out of the plastic.

I don't like drinking chlorine either, (I guess I'm one of the half educated guys), from what I know yes a bacteria can kill you now, but free radicals kill you slowly. 

The solution,... UV, or chlorinate in the tank, and filter when you drink it. I added ports so I can reach in and clean tanks. And drain completely, allow to dry, and refill with fresh every few months, (chlorinated municipal water). When I bought the boat I coudn't drink the tap water. Now it tastes OK. And smells better Too.

Filtering the vent line is a good idea, I'm going to try that, keep bad things from getting into the tank to begin with.


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## PaulfromNWOnt (Aug 20, 2010)

The *perception* of "good" water (sweet in this case) is based on a limited number of factors:
Temperature,
Odour,
Oxygen content,
Colour,
and Turbidity.

In short, if the stuff coming out of your tanks is clear, aerated, not stinky, and cold, you will *perceive* it as "good" water.

Will it actually be "good" is dependent on things other than perception.

As to some of the other points brought up here:

I don't care about 9 log removal for pathogenic bacteria because it's not telling me about viruses.

Crypto and Giardia can be filtered out easily at 4 log, but Crypto (the nasty one), and others can survive for quite some time in PURE chlorine, so that isn't going to cut it on it's own either.

UV is wonderful, but turbidity (the crap floating around in your water that you may or may not be able to see) can actually shield pathogens from the UV (and chlorine for that matter).

There's loads more, and I could literally go on about this stuff for days (it's my job), but suffice it to say that there is no single solution to the issue here. Multiple methods that are applied in a knowledgeable manner are better than a single treatment system.

Clorine WILL cause cancer, of that there is no question. The question is will the 200 plus years of life the average person would need to develop it be easily achieved. (based on a typical North American dosage of 1.2 ppm)


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## CarolynShearlock (Dec 3, 2010)

Unless you have aluminum tanks, most boats use chlorine bleach in the tank at a rate of 1/4 cup per 100 gallons to keep "crud" from growing. Then to get it to taste decent and remove anything else, a water filter. I think every boat should have a water filter instead of just lugging hundreds of plastic bottles of water aboard -- it's easier and certainly more environmentally friendly!

I recently posted on both the selection of a filtration system and on the different types of 10" filters on my blog -- my choice is a 10" filter housing on the drinking/cooking water faucet and a 0.5 micron charcoal block filter to remove not just taste and smell, but to further remove impurities.

A lot depends on what your water source is -- city water that you think is pretty good vs. rain water you're catching off the deck?

More info:

Water Filtering Systems
Choosing the Right Water Filter


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## hellosailor (Apr 11, 2006)

Bleach is easy. Reliable. Cheap. But I can't help thinking, a good UVC light in the tank with regular use should be even more effective. the downside is that you're mixing electricity and water, but this IS becoming conventional technology in air and water purification setups. Can't buy it for $2/bottle, but you don't have to filter it out and neutralize it, either. And it won't attack the plumbing.


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## fallard (Nov 30, 2009)

We find that carrying gallon jugs of "supermarket" water is not all that inconvenient for a 1-2 week cruise. We use it for coffee, tea, washing salad greens, and cooking. One gallon/person/day works for us and we use that formula for the yearly charter we do in the Caribbean. 

We use bleach and flush our tanks several times at the beginning of the season, so we are reasonably comfortable that water out of the tanks is safe and odor-free. After all, we use tank water for washing dishes, but the jug water provides an added comfort factor.


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## dhays (Jul 9, 2010)

How you chose to keep your water safe will depend on how you use your boat. For someone living full time on board, and refilling their tanks with reliable municipal water they would only need to use about 1/2 oz per 100 gal of water.

However, for someone like me, who weekends and spends a couple weeks cruising during the season, more is needed since the water can sit in the tanks for a longer period of time. I use 1 teaspoon for every 10 gallons in my tanks. This would be just a bit less than the 1/4 cup per 100 that Carolyn recommended. In actual practice, I put three teaspoons in my aft tank (32gal) and 5 teaspoons in my forward tank (55gal) when I refill the tank. That is even a bit less, but then I have a clean system and have a good water supply.

As others have mentioned, most water systems use chlorine to disinfect their water supply. Depending on the amount they have to use, it is possible to have trace amount of it still at your tap (or dock hose). My city uses a very small amount of chlorine due to the high quality of their source water (they own a good share of the watershed for the source river above where it is collected). If I lived in an area that had to use a lot of chlorine to keep their water supply safe, I wouldn't need to use as much beach in my own water tanks.


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## RichH (Jul 10, 2000)

rmeador said:


> RichH, what is the definition of "stagnant" water? If you're living aboard and refill your tank every two weeks, is that stagnant? What about once a week?
> 
> Also, if the municipal water supply has chlorine in it, are you still advocating adding extra chlorine to the tank (assuming I fill the tank without a filter)? Does it make a difference for the situation I outlined above vs someone who uses the boat once a week?


The Definition of 'stagnant water' is water that is 'moving' at less than 8-9 FEET per SECOND. A water velocity at 8-9 feet per second or greater will prevent/retard 'cell division' (bacterial growth) ..... and that is 'constant flow' or steady state velocity - *impossible* on a boat system.

Chlorine .... Chlorine is an oxidant and will combine with 'any' oxidizable surface (piping/hoses/tank,etc). The important aspect of 'chlorination' is there must be 'free' (uncombined to piping/hose/tank,etc.) chlorine in the water to be able to 'oxidize' the (common non-chlorine resistant) microorganisms. Forget 'recipes' as FREE chlorine is denoted simply by: the barest perceivable 'aroma' of chlorine in the water that you can detect with your NOSE - means that sufficient chlorine is 'available' in the water to affect a measure of 'sanitization'. Too much chlorine is harmful, too little is harmful (allows the microorganism to GROW) ... use your nose and develop a HISTORY of how your particular boat system takes (oz. of clorox per gallon of NEW water) to achieve the 'very barest perceivable' aroma of the chlorine/clorox. A standard 'dosage' of 1 parts per million chlorine (when using consumer grade 'clorox' (--- about 5% chlorine 'equivalent') will be 4-5 oz. per 100 gallons of water (*IMPORTANT* --- added to a hygienically *CLEAN* tankage) .... but use your NOSE and make corrections up or down to achieve the 'faint aroma'.

Importance of 'mechanical' cleaning .... contaminated water systems will typically have massive 'colonies' growing (if you feel a 'slime' or 'slimey' on your tankage components, you HAVE a massive colony of bacteria). Chlorine will only penetrate the 'uppermost' layers of the slime (calcyx), leaving viable organisms alive below the 'stunned'/killed layer ... and if the conditions are 'right' will easily and rapidly 're-infect' the WHOLE system. Nothing beats a scrubbing brush + soap and water !!!!!!!!! 
Once a boats water system is CLEAN & 'sanitized', its soooooooooo easy to keep it that way simply by adding minute amount of clorox/chlorine and using your nose to keep the proper amount of chlorine in the water .... plus adding a filter (RATED for the retention of quite COMMON chlorine resistant 'oocysts', etc.) to the hose that you use to fill the tank.)

hope this helps.


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## lancelot9898 (Dec 30, 2008)

I have two 60 gallon tanks and having lived aboard for a number of years never did have a need to treat the water since it was being used at a pretty good rate and the water source was a city water supply. Now that I no longer live aboard the useage has gone down, but I'm still not experiencing any problems. It could be because each winter I drain the water tanks as much as possible and put several gallons of the non toxic pink antifreeze into each tank. Not sure if that has any benefical effect on water quality but so far so good.


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