Cleaning Water Tanks & Lines

Allen · Post by **Allen** » Wed Oct 08, 2008 7:32 am

I've read that you use 3/4 of a deciliter of beach (1/10th Liter) per lither of tank capacity. I've also read you use 3/4 cup/10 gallon capacity. Does anyone know for sure what the ratio is?

Quetzalsailor · Post by **Quetzalsailor** » Wed Oct 08, 2008 9:26 am

I don't know the ratio that you're supposed to be able to tolerate. It's more than is found in city water, though. We tried the teensy ratio in the previous boat and apparently, my ratio is far lower.

I suggest you scrub and flush as best you ever can, including using plenty of bleach (as much as for doing laundry or even worse). Then flush with fresh water until you cannot smell even the merest hint. Then use Aquabon in the proportion that's given on the bottle.

The 110 gallon tank in Quetzal was stomach-turningly bad a couple days after filling back when we bought the boat. After thorough cleaning, sealing the lid, replacing the mis-mash of repaired water lines, bleach, and flush, the water would stay adequate for several weeks. The following seasons, I'd empty the tank, and fill only the waterlines with the antifreeze; come spring I'd flush the antifreeze, fill the tank, and use the Aquabon. The water now stays perfectly fine for the season; even Sue wonders why she continues to bring bottled water for coffee and tea.

Hirilondë · Post by **Hirilondë** » Wed Oct 08, 2008 5:36 pm

If you are going to flush the tank out well after cleaning I don't think the amount of bleach you use is critical to health. The other thing is that bleach evaporates from water if ventilation is provided. To be safe, you can always leave the fill cap off for a couple days to let any residual chlorine evaporate.

Allen · Post by **Allen** » Wed Oct 08, 2008 6:59 pm

I had actually read somewhere that chlorine bleach is harmful to stainless steel which is what my water tanks are made of.

Rachel · Post by **Rachel** » Mon Oct 13, 2008 12:53 pm

I understand that to be true as well, although I'm not sure where the cut-off between benign and harmful concentrations is.

I used some other mixture for cleaning (forget now: baking soda and vinegar maybe?) stainless steel tanks, but did still use the slight amount of bleach recommended for treating the potable water in the tanks.

Do you have the option to simply physically scrub the tanks (i.e. clean-out ports)?

I've replaced lines that were old/dirty rather than clean them (once they get past a certain point).

Rachel

Post by **Tim** » Mon Oct 13, 2008 1:10 pm

Allen wrote:I've read that you use 3/4 of a deciliter of beach (1/10th Liter) per lither of tank capacity. I've also read you use 3/4 cup/10 gallon capacity. Does anyone know for sure what the ratio is?

Here's what ABYC has to say about the addition of bleach to water tanks for the purposes of disinfection.

Allen · Post by **Allen** » Mon Oct 13, 2008 5:36 pm

Tim do they elaborate on what and where to get Chlorinated Lime, HighTest Calcium Hypochlorite and Liquid Sodium Hypochlorite? Are these items used individually or do you need to mix them?

I was hoping I could just use plain old Clorox bleach. :(

Rachel, I can get into the tanks but I also want to purge the lines which have been in use for only a few months.

Rachel · Post by **Rachel** » Mon Oct 13, 2008 10:28 pm

I think "Liquid Sodium Hypochlorite" is household bleach.

Okay, double-checked and found this on Wikipedia:

Household bleach sold for use in laundering clothes is a 3-6% solution of sodium hypochlorite at the time of manufacture. Strength varies from one formulation to another and gradually decreases with long storage.

Here's a link to the rest of the article:

http://en.wikipedia.org/wiki/Sodium_hypochlorite

Peter · Post by **Peter** » Mon Oct 13, 2008 11:53 pm

My favorite tank and water line cleaner is Hydrogen Peroxide in 3% solution.

Chlorine is not my favorite thing to ingest, which is why I filter it out of my drinking water at home. And it's not just chlorine that's being used in Municipal water systems, it's "chloramine", a mixture of chlorine and ammonia. I'll jump down from the soap box now ;-)

Allen · Post by **Allen** » Tue Oct 14, 2008 4:57 am

Thanks Rachel :)

Allen · Post by **Allen** » Wed Oct 29, 2008 2:13 pm

Out of curiosity I wrote to Clorox and ask them this question. Here is their response. Note, this refers to regular Clorox Liquid Bleach, none of the products with additives.

Clorox Liquid Bleach can be used to clean tanks in boats or recreational vehicles before using them to store water. Fill the tank with water and add 1 cup Clorox Liquid Bleach for each 50 gallons of water. Leave this solution in the tank for ten minutes and then completely drain it. Turn on any faucets to run this solution through water lines. Rinse the tank with purified water through the water lines until the taste of Clorox Liquid Bleach is gone. By following these directions, we would not expect any damage or discoloration to occur in a stainless steel water tank, however, we would not recommend using this product in an aluminum water tank. Aluminum is very easily damaged by any product containing chlorine bleach.

To purify the water for drinking, we recommend using 1/4 teaspoon of Clorox Liquid Bleach to one gallon of water, let sit for 30 minutes. After this time there should be a slight chlorine odor to the water. If the slight chlorine odor is not present, repeat the dosage and wait 15 more minutes.