1 gallon = 0.1337 cubic feet
Crumpet Water Tanks:
5.5ft x 1.5ft x 0.75ft = 6.1875 cubic feet per water tank
6.1875 / 0.1337 = 46.27898 gallons per tank
At 5 oz per 10 gallons, put 48 oz (1 ½ qt) into 100 gallons
Common Guidelines; Use a cup per 10-gallon solution for deep cleaning of stale tanks.
Use 8 drops per 10-gallons for purifying drinking water.
Water tank maintenance:
From Denece Vincent on The Live-Aboard List:
[To clean water tank,] ... use spa shock (bromine) to kill any leftover creatures. Let it sit for a
day. Siphon and rinse at least twice. Bromine tends to leave a lot less stink in the tank but is as
effective in killing bugs and algae. ... We have fiberglass tanks and chlorine tends to hang in
From Randy on the live-aboard mailing list:
[Re: water woes (water filter rapidly becomes clogged, feels slimy):]
Sounds like it may be an algae bloom. We have aluminum tanks and get those periodically ...
usually in the spring. I suspect it is related to the warming of the water after the cool/cold of
winter. We used to run bleach in our tanks to provide an extra measure of chlorination (approx 1
oz per 50 gal) but that takes its toll on the charcoal brick we have inline, so we switched to 35%
food grade hydrogen peroxide about 3 years ago. It is as effective with the bacteria killing, and
not as hard on the charcoal filter ... in fact it is odourless and tasteless. Unfortunately we have
noticed that the algae blooms are a regular annual occurrence since going to the H2O2, where
they were much more infrequent when using bleach. Still puzzling it over, we may go back to a
Having said all that, when you do get a bloom, you need to "shock" the tanks. That means high
dosage of chlorine. I use approx 1 litre of normal household bleach per tank (approx 55 imperial
gallons). Fill the tanks with water and let sit for an hour or so. Drain tanks, fill with water and
drain again, add 1 litre vinegar to tank and fill with water, let sit a bit, drain, rinse once more
with pure water, and you're done. It goes without saying that while all this is going on you want
your water pump turned off. Or pull your filters and allow the high concentrate water to flow
through the system, shocking the whole works. Just keep in mind you'll then need to flush the
whole system with water/water-vinegar/water. BTW, the vinegar is to kill the residual bleach.
I've done it without, but man-o-man, you can rinse for hours and the water still tastes/smells
Sanitize water system:
1. Use chlorine (bleach) solution for 3 hours.
1. Flush with fresh water.
3. Clean the filters.
4. Use vinegar solution for a day or more.
5. Flush with fresh water.
6. Clean the filters.
From Jerry Donofrio on The Live-Aboard List:
... Be sure to add the bleach so that it gets into each tank and mixes well. Generally I put the
bleach in about halfway through the fill cycle. After it have the tanks filled to the top be sure to
run the mixture through the lines and out the hot and cold water taps everywhere on the boat.
The odor should be a very strong bleach smell. Let the bleach mixture stay in the lines for 24
hours and then empty and refill twice. The bleach smell should be gone. If not - use a little white
vinegar to sweeten the water or use baking soda. I have used both and prefer the vinegar. ...