# Fresh water tank slime



## TSOJOURNER (Dec 16, 1999)

I recently purchased a 1990 Catalina 28. The fresh water tanks keep giving off a sort of gross slime that gets clogged in the pump filter and smells awful. I have tried to scrub the tank as best as I can via the access cover. I thought I had it clean but the crud came back. Have tried moderate amounts of bleach. The Blob lives. Any ideas? Thanks.....
Dave


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## jack_patricia (May 20, 2001)

Dave, the first question that leaps to mind is ''where do you get your water''? Before you say the city water''s fine, ask around the marina about any other folks having this problem. Marina water delivery systems can be a big problem.

I''d recommend you a) eliminate the existing problem, and then b) guard against reintroducing it. For a) I''d close the tank supply line, fill the tank with an agressive clorine bleach/water mix, then carefully top up the fill hose with the same mix to the very top (which will also drive the mix up your vent hose). During the ''fill'' process, run sufficient water thru your hot water heater (if equipped) and both H & C taps of each fixture so that all your supply lines and heater tank are also being purged. Let it sit most of a day, then repeatedly flush, tank empty/tank full/tank empty. (BTW don''t do this if you have an aluminum tank, which you probably don''t). Flush using every fixture, hot & cold taps. This assumes you''ve got the tank scrubbed as best you can before beginning; dead bio organisms aren''t going to leave the tank but rather just sit there and float disgustingly around.

For b), consider using an activated charcoal 5 micron filter system hooked up to your dock hose, available at Lowes/HD for perhaps $40. And of course, continue treating the water altho'' that won''t prevent mini-blobs from being delivered to the tank. After filling the tank a time or two, extract the (reuseable) filter and examine it; what are you seeing that otherwise would be going into your tank? If it''s pretty visible, I''d recommend showing it to the marina staff. That''s a great way to objectively demonstrate they may have a line breach somewhere or are taking on bio-polluted water from their supplier.

Good luck with Blob Eradication!

Jack


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## TSOJOURNER (Dec 16, 1999)

Thanks for the input. The marina water does not seem to be a problem for others. Good idea re the fill up to include the hoses. Tanks are poly, not aluminum and there is a water heater. 

Dave


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## RichH (Jul 10, 2000)

What you have is a mold/mildew contamination. 

What you have to do is get in there and mechanically scrub the system (replace hoses if stained brown, etc.) The mechanical removal of debris will lessen chances of reinfection; dead cells and stunned spores, etc. left in the system will provide nutrients for further infection. Some of these species are EXTREMELY toxic to humans, especially if the spores are breathed-in. WEAR rubber gloves, goggles and at least a dust mask when cleaning such bioburden from the tankage !!!!! That the tanks are fouled also suggests that the boat has a LOT of infection under the hidden walls, floor boards, etc. The vector of contamination isnt city water but the TANK VENT: sucks in spores as you draw down the water. .... Clean or REPLACE the tank vent line. Once the system is cleaned I suggest that you wrap the entrance of the vent with a big wad of sterile gauze, keep it dry and change yearly. 

Then go after all the "BLACK SLIME" that lives in all the dark places on your boat, use Chlorox spray, etc. and be SURE to wear the protection listed above. When closing the boat for long periods of time consider to place in loose paraformaldehyde crystals to kill more of the mold/mildew. Vent the boat to allow the para-F gas to vent out BEFORE entering. 


Once you mechanically remove the tank debris, shock sanitize the whole system: tanks lines, faucets, pumps ..... and VENT with a STRONG solution of Chlorox. 

If youre not "afraid of chemicals and KNOW how to use them" a caustic dilute solution of Sodium Hydroxide that is allowed to soak for period of time will dissolve the bio debris remaining after mechanical scrubbing. The system is then scrupously flushed with water, then neutralized with a mild acid (vinegar) ..... then Shock sanitize with Chlorox. Dont use caustics if you dont know how to use them or if you dont understand the harm caustics can cause or the personal protection needed.

After the system is cleaned add fresh water and add enough Chlorox.... so that you get just the faintest perceptable smell of Chlorox in the outlet water to keep the ''critters'' stunned and unable to reproduce. Dont follow ''recipies'' ... just use your nose to get the "faintest possible chlorine smell" from the output water. Adding more that this amount is harmful- many authorities suggest that excessive chlorination of water can lead to cancer, and other metabolic disorders etc.

The use of carbon filters installed in the tankagae lines, etc. is STRONGLY NOT recommended as the carbon is a nutrient source for bacteria etc. PLUS it will adsorb the active free chlorine used for maintenance. If you MUST use carbon for odor removal etc., use it ONLY on the hose that you use to fill the tank. 

Hope this helps.


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## jack_patricia (May 20, 2001)

Rich, could you say a little more about how you arrived at the following advice:

"The use of carbon filters installed in the tankagae lines, etc. is STRONGLY NOT recommended as the carbon is a nutrient source for bacteria etc. PLUS it will adsorb the active free chlorine used for maintenance."

If the activated carbon filter lies downstream of the tank,just ahead of the taps, I don''t see how chlorine absorption is an issue. The water has exited the tank and is on its way to the user. The ''nutrient source'' comment is also a bit of a puzzler: is your concern for water remaining overnight in the AC filter body? How is a tank water microbe benefiting from a filter downstream?

Your advice is contrary to everything I''ve read; can you offer us a cite or two where we can follow up? Thanks.

Jack


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## RichH (Jul 10, 2000)

This is a phenomenom of ''chemical equilibrium'' meaning if the carbon is ''hungry'' for molecules/iond and those molecules/ions are present in the system (even if not flowing) these molecules (in this case chlorine ions) will migrate and affix to the surface of the carbon. What happens is that the carbon will remove the Chlorine from the system and leave NO chlorine in the system to ''stun'' any remaining bacteria, spores, etc. 
sooooooo even if the water isnt flowing, the ions ARE flowing and in this case TO the carbon filter. The only way to prevent this ionic migration is to shut the valves on the carbon filter each time you use it. 

Its not a big problem in a household system as enough chlorine will constantly migrate in from the system supply even if the supply is non flowing. ..... but on closed system such as a boat, there no replentishment possible except for continually dumping more Chlorine into the tank. 

I''m deeply involved in water systems and especially filtration. Why I DO NOT have (ANY) filters installed on my boat''s water system are: 1. Trapped bacteria, molds, etc. on a filter eventually dies and the accumulated (now highly concentrated!) cell debris (endotoxins) can release from the filter and reenter the system ... gives you FEVER, etc. A filter concentrates the bacteria. 2. Many bacteria THRIVE on carbon as they use it as part of their nutrient source (consider that most of YOUR food is also carbon based... and what your cells eat is essentialy: glucose).... long term, bacteria will even ''eat'' the carbon from steel pipes, etc. , etc. (.... thats probablly how metal ores were formed in the earth.... bacteria ate away the carbon). 
The data sources are limitless ... just do a websearch for "USP water", "Water for Injection" (WFI water), "validation of water systems" etc. etc. From these searches you will find zillions of sources and documentation (including US-FDA regulations) of purity water systems.

Just be aware that the stagnant water system on a boat is VERY close to a bacteria, etc. incubator - non-moving, dark, warm, .... so in my mind why would I want to also supply food (carbon) to enhance cell growth !!!!!

A good ''starter'' reference would be "Pure Water Handbook", Osmonics Corporation. 2ed. 1997 (paperback) ph: 612-933-2277 ($10). But the handbook DOESNT cover "stagnant" systems.
However, current ''bottled'' water specs. would probably apply as the "bottle" on my boat is 120 gallons. 

hope this helps.


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## RichH (Jul 10, 2000)

This is a phenomenom of ''chemical equilibrium'' meaning if the carbon is ''hungry'' for molecules/iond and those molecules/ions are present in the system (even if not flowing) these molecules (in this case chlorine ions) will migrate and affix to the surface of the carbon. What happens is that the carbon will remove the Chlorine from the system and leave NO chlorine in the system to ''stun'' any remaining bacteria, spores, etc. 
sooooooo even if the water isnt flowing, the ions ARE flowing and in this case TO the carbon filter. The only way to prevent this ionic migration is to shut the valves on the carbon filter each time you use it. 

Its not a big problem in a household system as enough chlorine will constantly migrate in from the system supply even if the supply is non flowing. ..... but on closed system such as a boat, there no replentishment possible except for continually dumping more Chlorine into the tank. 

I''m deeply involved in water systems and especially filtration. Why I DO NOT have (ANY) filters installed on my boat''s water system are: 1. Trapped bacteria, molds, etc. on a filter eventually dies and the accumulated (now highly concentrated!) cell debris (endotoxins) can release from the filter and reenter the system ... gives you FEVER, etc. A filter concentrates the bacteria. 2. Many bacteria THRIVE on carbon as they use it as part of their nutrient source (consider that most of YOUR food is also carbon based... and what your cells eat is essentialy: glucose).... long term, bacteria will even ''eat'' the carbon from steel pipes, etc. , etc. (.... thats probablly how metal ores were formed in the earth.... bacteria ate away the carbon). 
The data sources are limitless ... just do a websearch for "USP water", "Water for Injection" (WFI water), "validation of water systems" etc. etc. From these searches you will find zillions of sources and documentation (including US-FDA regulations) of purity water systems.

Just be aware that the stagnant water system on a boat is VERY close to a bacteria, etc. incubator - non-moving, dark, warm, .... so in my mind why would I want to also supply food (carbon) to enhance cell growth !!!!!

A good ''starter'' reference would be "Pure Water Handbook", Osmonics Corporation. 2ed. 1997 (paperback) ph: 612-933-2277 ($10). But the handbook DOESNT cover "stagnant" systems.
However, current ''bottled'' water specs. would probably apply as the "bottle" on my boat is 120 gallons. 

hope this helps.


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## TSOJOURNER (Dec 16, 1999)

Hmmmm. Lots to work on. I planned to remove the two tanks, bow and starboard, to clean them. Will check the hoses as well. The slime I have is clear to milky. I h aven''t seen any black or brown. Rich, thanks for taking the time for such a detailed response!

Dave


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## hamiam (Dec 15, 2000)

I wonder if white vinegar would work for your problem.


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## TSOJOURNER (Dec 16, 1999)

Our research indicates that Hydrogen Peroxide, the cheap stuff sold at all stores, will or shold keep the water in the tank free from bacteria, and not harn you if you ingest it. I am not sure of the mixture. I believe its one teaspoon per gallon. I''ve used it in my tanks and have not had any problem at all.


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## TSOJOURNER (Dec 16, 1999)

Well I think the Blob has been tamed. I used the agressive bleach approach and flushed all the lines. I think the bugger was living in the hot water lines, at least that produced the most crud after the bleach sat for awhile. I also removed and cleaned all the aerators, mucho crud. So at least for now the good guys have won. Will monitor closely for any reappearance, and many thanks to all for their time and suggestions. 

Has anyone else tried the hydrogen peroxide for maintence? It would taste better than chlorine!

Dave


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## RIGMAN60 (Apr 1, 2005)

Poly Pipe As A Replacement For Fresh Water System (galley) Existing Braided Hose? Brand,ease Of Use? Feeding Bending Fittings /
Thanks


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## Volkhard (Feb 19, 2006)

Interesting topic with lots of information. But, what needs to be done to keep a system fresh that is outfitted with an unaccessible Aluminum tank? For what I Know, bleach is out of the question .... I haven't developed any slime or odors but I am concerned and want to do a preemptive strike BEVOR the problems manifests itself ...
I hope, I am not hijacking the threat. I assume I am not the only Aluminum tank boat-owner following this threat with interest.


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## scottyt (Jul 19, 2008)

according to peggy hall a stronger but short dose of bleach is okay for AL tanks. she said its no different that years of low dose from public water. 

i have a fiber glass tank and i gave it a real strong ( like 1 gallon to 36 of water ) does over night to kill it all then drained and refilled with fresh several times.

i had clear slime, not black. it did come back very slightly but sense i am now using the tank a lot more its not a problem. i know in the navy ( subs ) our tanks had clear slime and they tasted okay, when/if it got cleaned out the water tasted terrible for a few months


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## scottyt (Jul 19, 2008)

> People have expressed concern about using this method to recommission aluminum tanks. While bleach (chlorine) IS corrosive, the effect of an annual or semi-annual "shock treatment" is negligible compared to the cumulative effect of holding chlorinated
> city water in the tank for years. Nevertheless, it's a good idea to mix the total amount of bleach in a few gallons of water before putting it into either a stainless or aluminum tank.


quoted from here


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## DropTop (May 7, 2009)

I put water purification tablets (the kind used when hiking or camping) in my poly tank every time I refill it. I normally use about 60-70% of the dose they reccomend for the # of gallons I fill because I carry bottled water for drinking and only use the house water for cooking (boiling water only) or washing hands / brushing teeth. I have not yet had any cases of slime or odor in the water yet.


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