Cleaning Water Tanks

[Arcsurf]

Looking for advice on cleaning my water tanks. Can something be circulated through the system to do the job?

[Calif.Ted]

For plastic tanks usual process involves draining and refilling with clean water and a little bleach, let sit 24 hrs. then drain and refill. Sometimes takes a few rinses if you are too heavy with the bleach. For Metal tanks bleach can be problematic and I can't remember the alternative.

[Arcsurf]

Yes I have metal tanks and that is the concern - that bleach is corrosive - not to mention on all of the plumbing and pumps.
That is my concern with bleach.

[phorvati]

my metal tanks had inspection ports big enough to reach into deep corners. I was surprised as to the amount of rubbery film on the surfaces. I had no mold just this gummed up film. I sprayed foaming bleach cleaner and scrubbed the walls. Then filled and drained them few times. The first winter/off season I left tanks full of water with higher than usual bleach content. in the spring I rinsed them by flushing 2-3 times over and that was it. I had to change hoses as they are usually much moldier than tanks.

[Bowdrie]

Originally Posted by Arcsurf

Yes I have metal tanks

And there are no removable clean-out ports?
If not, and you have good access to the tank tops a clean-out port can be installed but not the easiest of jobs.
As a previous post mentioned, the scum/crud, and even little monsters, (look like pieces of lettuce floating in the water,) generally need to be scrubbed out.
I hesitate to recommend any chemical product.
By all means get a filter that screws onto the garden hose to fill the tanks, something ~2microns, use another one in the boat.

[GreenWave]

Use hydrogen peroxide. Much safer for you and the parts.

[hlev00]

I had heard others using beer line cleaners. I can't speak personally of it though it did sound like an interesting idea.

[Kello]

Howdy, been there dun that. My goode olde boat had stainless tanks with a massive algae problem from sitting for sale for so many years. First I tried brushing and soap and other benign and time-consuming and useless procedures. Clorox / chlorine is verboten for stainless, so what to do? I spent hundreds of dollars on 70% peroxide solutions, didn't work but it did blow a water filter off it's mount. An olde salt recommended vodka (as per his dad) and all that did was make the algae get drunk and grow thicker. Tried to live with the algae, but where I've been living has some of the worst water "quality" in the USA so the cost in filters was prohibitive.

Fortunately one of the stainless tanks finally sprouted a leak, and I built in fiberglass tanks, which I can disinfect with Clorox at every tank filling.

Whether your tanks are Aluminum or Stainless, someday they WILL fail, schedule six months for yourself to build new fiberglass tanks when it is convenient for you (never, lol, just do it).

[dohenyboy]

You can use bleach in metal tanks but you need to flush it out thoroughly after a couple of hours.

[CrispyCringle]

I agree. Tap water has chlorine in it and its in the tanks 24/7. A relatively short exposure to a higher concentration isnt going to eat through the tank. I use Peggy Hall's suggestion of approx 1 oz bleach per gal. Fill tank, run ALL water lines until you smell bleach, and let sit about 24 hrs max. Empty tanks, and refill, run every line until no bleach smell. I also find it helpful when filling a tank to run it completely dry and then start filling with the pump running. This will help get out the last of the old water. Turn off the tap and continue to fill after a gallon or so of the old-new water mix has been drained out.

A source of bio-ingress for both fuel and water tanks is the breather vent. Ive yet to find a good inline filter for this. Dont know what spec would be effective. Havnt given it a lot of effort actually. But If I come across something, Ill get it.

[Cheechako]

Well, it sounds like you need physical cleaning first. Algae you kill with chemicals can still cling to the tank. Do you have access covers? Rent a pressure washer and do that everywhere you can. Pump it out as you go while the debris is floating around.

Chlorine is fine in stainless temporarily. Add it to your tank, go out and motor around or sail so the water action splashes around in the tank. Come back to the dock and pump it out.

[Cowpoos]

Find some Chlorine Dioxide, sometimes found as tablets or occasionally a liquid. As a liquid, there is a definite shelf life so be aware.

Empty and rinse tanks. Full tanks and dose appropriately with your chlorine Dioxide.

Done. Open beer.

[hugosalt]

If considering installing access panels.
Boyd Welding makes both Aluminum and SS access panels, each in two sizes.
Inexpensive, easy install and excellent products.
I installed one on my fuel tank years ago.
There main business is making tanks for automotive industry.
In Alum. $40. larger $60.
In SS $80. larger $120.

[thinwater]

Re. Cleaning stainless water tanks, Google using weak acid. Most agricultural cleaning of livestock watering systems is done with the rough equivalent of vinegar. Many food grade applications as well. Chlorine is not the only approved method, nor the most effective for severe contamination.


https://poultry-science.uark.edu/_re...e_Sept2017.pdf


Also, if there is no large access port, you can use numerous tips on power washers to hit the corners. Be wary of the jets that are aimed back at you (wrap a big towel around the entry).



https://www.amazon.com/Nozzles-Conne...ps%2C68&sr=8-6


Don't get stuck on one path.

[Pandor]

Originally Posted by CrispyCringle

I agree. Tap water has chlorine in it and its in the tanks 24/7. A relatively short exposure to a higher concentration isnt going to eat through the tank. I use Peggy Hall's suggestion of approx 1 oz bleach per gal. Fill tank, run ALL water lines until you smell bleach, and let sit about 24 hrs max. Empty tanks, and refill, run every line until no bleach smell. I also find it helpful when filling a tank to run it completely dry and then start filling with the pump running. This will help get out the last of the old water. Turn off the tap and continue to fill after a gallon or so of the old-new water mix has been drained out.

A source of bio-ingress for both fuel and water tanks is the breather vent. Ive yet to find a good inline filter for this. Dont know what spec would be effective. Havnt given it a lot of effort actually. But If I come across something, Ill get it.

If Peggy’s recommendation is really 1oz bleach per gallon, that is about 8x the recommended amount.