# Water Purification



## TSOJOURNER (Dec 16, 1999)

In addition to using an in-line filter when filling water tanks, does anyone recommend adding a biocide to the water?


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## yotphix (Aug 18, 2006)

Being bio myself and not wanting to cide I recommend not. If you are filling from chlorinated municipal water supplies the water will be safe. If you are concerned about it you could do a periodic flush. Fill with water and killer chem of your choosing and empty. Refill and enjoy! If you are filling at docks in questionable places then ignore me and cide away


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## Cruisingdad (Jul 21, 2006)

Many of the cruisers I know, myself included, use periodic additions of bleach. It will not hurt you in small quantities (in large quantities will give you diarhea). We have 2 seperate tanks and typically bleach one of them a tad more than the other as it is typically used for shower.

If you are living aboard and or cruising, you will find that this is not all that neccessary very often as you will go through the water quick enough not to worry about it. If your boats sets up a bit, it may be more neccessary. You will get a growth in your tanks without some caution.

We have tried a few different systems for post filtration (drinking water), but have settled into a cheap Pur water filter pitcher with a charcoal filter on top. You can get them at Walmart and they are cheap. It fits in the fridge and thus you can keep cold water on hand. It takes not pressure to push it through and you can store a lot of the filters for long-term runs. 

Just our experiences. You may find something else that works better.

- CD

PS I imagine from your posts that you will have a watermaker on board - thus your water should be very clean going in. Just worry about post-build-up.


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## sailingdog (Mar 19, 2006)

BTW, bleach is not really all that effective long-term.. it works well when it is first added to the system, but not for very long. In higher concentrations, it will kill all the stuff living in your water system....as in a shock treatment. Be aware that it does attack certain components that may be in your water system... like rubber seals, metal parts, etc.


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## jerryrlitton (Oct 14, 2002)

A friend of mine said that the bleached water tasted better when he added a 5th of JD in his 100G tanks.


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## sailingdog (Mar 19, 2006)

Also, you don't want to use any chlorine in the water if you need to use it to flush the membrane on a RO watermaker. Chlorine will destroy the membrane.


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## erdagte (Nov 18, 2000)

*What about vinegar?*

I heard that vinegar was better than bleach for adding to your tanks. I'm not too concerned about taste, just health. 
Comments?


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## sailingdog (Mar 19, 2006)

Vinegar is a great way to clean the tanks, neutralize funny tastes, and get rid of mineral deposits..but it does not kill most bacteria...not enough to be considered a shock treatment of the water system.


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## erdagte (Nov 18, 2000)

Thanks sailingdog... but if not bleach or vinegar... what should I use? Or does it even matter?


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## sailingdog (Mar 19, 2006)

The best way to prevent growth of stuff in your tanks is to shock treat the tanks properly, using chlorine bleach, and then to keep the water moving through the system. *The only time you really get nasty growth in a good fresh water system that has been shock treated properly and filled with clean water is if the water sits stagnant for an extended period of time.*

Also, you should avoid putting any water that is questionable into your water tanks. Pre-filtering the water, with a strainer will help keep a lot of the gunk out of the tanks. You should wash down the deck in the area of the water tank deck fill, to help remove any dirt and gunk that may otherwise get washed into the water tanks from that area, prior to filling your water tanks.

If you use a hose in a marina to fill your tanks, make sure that you run the water long enough to flush what ever has been sitting in the hose and baking in the sun. That may take a few minutes, but the water coming out of the hose, when you are about to fill your tanks, should be fairly cold, and fresh out of the underground water main.

Obviously, if your marina uses a large, above ground tank or cistern, then this may not be the case.

Hope this helps.


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## erdagte (Nov 18, 2000)

Yep, it sure does help. I use the water in my tanks daily. I'm not too particular about taste, etc... just as long as it doesn't give me the nasties. But after reading your post, just to be sure, I'll run a shock treatment with bleach instead of vinegar (btw, I have stainless steel tanks, if that makes a difference). And the prefilter idea can't hurt.

Thanks again!


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## hellosailor (Apr 11, 2006)

The only real option to bleach is iodine. Either crystals, or plain (clear, not red colored) "tincture of iodine" which is iodine dissolved in alcohol. 

Bear in mind that common table salt is IODIZED because most of us do not get enough iodine in our diets. Too much iodine will leave a taste in the water, but a charcoal filter or other means will remove that. You can get iodine from most pharmacies, definitely tincture if they don't have crystals. "Polar Pure" water purifier is a special jar kit of iodine crystals.

If you wanted to do a little investing and go chemical free, UV-C ("C" band UV lighting) breaks down DNA quite aggressively. Bacteria, viruses, parasites, all get disrupted by it in no time flat. You can buy a UV-C water treatment lamp, which is normally installed as the last part of a home water purificiation system, and either install it before your faucet, or in your water tank. There are even two portable versions of this ("SteriPen" is one) sold in camping stores for treating water.


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## sailingdog (Mar 19, 2006)

Also, you should be aware that some of the saltwater parasites aren't affected much by iodine, as there is plenty of it in seawater. 


BTW, if you do you chlorine bleach in stainless tanks, let the tanks breathe for about 45 minutes to help neutralize the chlorine. Chlorine bleach attacks stainless steel, and 304 is far more affected than 316 alloys IIRC.


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## hellosailor (Apr 11, 2006)

Saltwater parasites in the FRESHwater tank?

Hey, there could be a while ecosystem in there, I"m just looking at what's known to come along with "fresh" water. What kind of saltwater critters have you found in the fresh water supply?


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## TSOJOURNER (Dec 16, 1999)

Clean Tabs Ltd makes a product called Puriclean to 'clean and purify all stored water systems.' The companion product, Aqua Clean, treats the water after the tank is clean. Aqua Clean claims to 'guard against illness caused by contaminated water and destroy organisms which cause Legionellas, Cholera, Diarrhoea, Typhoid, Amoebic Dysentery and Salmonella.' They've been used by boaters in Chicago for years and I've never heard a complaint about these products.

One side note, don't assume that marinas and boatyards have potable water. That's not always the case.


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## erdagte (Nov 18, 2000)

My marina water is good and at sea I have a watermaker (save that for a new thread). But the tanks sat stagnant for about a year. I flushed out the system twice a few mnoths ago. I used vinegar (because I didn't know any better). Now I'll do it again with bleach. But assuming I have to fill the tanks, that's a 120 gallons and a lot of pumping.

I've seen Puricleann / Aqua Clean, but haven't given much thought to it. Again, from what I'm reading here, if your marina is serving you good water and you use your tanks regularly, then you should be okay.


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## Teredo (Sep 25, 2006)

'My marina water is good' 

How do you know?


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## erdagte (Nov 18, 2000)

The doc tests it every month.


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## hellosailor (Apr 11, 2006)

"I've seen Puricleann / Aqua Clean," That seems to be chemically the same "bleach" used as a commercial pool cleaner, plus an optional second chemical to neutralize some of the flavor. IOW, a solid form of bleach.


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## sailingdog (Mar 19, 2006)

hellosailor said:


> Saltwater parasites in the FRESHwater tank?
> 
> Hey, there could be a while ecosystem in there, I"m just looking at what's known to come along with "fresh" water. What kind of saltwater critters have you found in the fresh water supply?


One of my friends got pretty sick during a longer passage in really rough weather...as enough salt water got into the freshwater tanks through the deck fill being under. They knew the tank had gotten some salt water in it and were "purifying" the water with iodine tablets that they had from a camping store. Don't know what it was that made him ill, but he had five days of the runs... UGH...


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## hellosailor (Apr 11, 2006)

Sailingdog-
Iodine CAN give you the runs, for the same reason that antibiotics often will. Iodine kills all the microcritters, and if there's enough of it in your drinking water, it will neatly kill all the intestinal bacteria just as neatly. Ooops, no bacteria, the gut stops working right.
I'm not sure how dosage-sensitive that is, can't seem to find any information on the web about how much is too much that way.


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## sailingdog (Mar 19, 2006)

True, but I don't think they used that much iodine...However, I wasn't there... so I can't say exactly what happened for sure. Might have been the increased iodine from the salt water...but in either case, I wouldn't want the runs for five days..


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## hellosailor (Apr 11, 2006)

"I don't think they used that much iodine"
For some people, yogurt improves intestinal critters, for others, just one cup will trigger lactose intolerance and runs. I'd guess iodine tolerance would also vary with the victim, and how healthy the victim's "critters" were to start with. Like h.pylori (the stomach ulcer bug) and how acidic your stomach is, some people just have difference ecosystems in there.


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## TSOJOURNER (Dec 16, 1999)

If there is no light then you can never grow algea. Most tanks really are dark inside and so this is not the issue. Algea is a plant that requires sun light.

The issue is what water you choose to put in the tank. Pre filtering water before you add it to the tanks goes farther than anything else. You can rig up a set of two stage whole house filters that you can connect up to your hose to fill your tanks with filtered water. In a dark tank water can stagnate for a long period of time and still be safe. In a tank that gets sun light it won't last more than a week or so and you can never keep it clean.

Publicly treated water is about as chlorinated as required adding more won't really improve the safety of the water. Adding other chemicals probably won't help either. Perfoming a shock treatment on the tank does not require a very high level of Chlorine and should not be needed regualrly. Using a higher does really won't do much more. You need to be kind to your plastic plumbing and high concetrations of chlorine won't help. Don't play chemistry set with your drinking water.

If the water needs Iodine I'm not putting it in my tank.

Adding a tap filter is not a bad way towards making your water taste a bit better either. Put the most attention to what you put inside the tank in the first place. You can't make a cocktail that will clean contaminated water once it is inside the tank.


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## hellosailor (Apr 11, 2006)

Paul-
Never say never.<G>
" Photosynthetic Algae Altered To Grow Without Sunlight

For the first time, scientists have introduced a fundamental metabolic change in a single-celled alga so that it no longer requires light to grow. 
Photosynthetic algae are the major primary producers in aquatic environments. They are also used in industry for food, to make pigments and cosmetics, and for other applications.

Until now, these organisms have mostly been grown in open ponds where the variability of the environment, light limitation and contamination with microbes are frequent problems.

Scientists have now found that by inserting just one gene that catalyzes glucose transport into the diatom Phaeodactylum tricornutum, the organism can thrive in the dark, getting its energy exclusively from the glucose.

This marks a critical first step toward large-scale, high-density, cost effective cultivation of algae using fermentation technology. The results of this study are published in today's issue of Science."
[from http://unisci.com/stories/20012/0615013.htm ]

What about the stuff that grows on the water interface in diesel tanks? Isn't that biomass algae also? Growing without air or light?


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