Restoring Fresh Water Tank

[mervynmitchell]

I have bought an Alajuela 33 with stainless a steel water tank in which the water has remained unused for some time (2-3 years) and is stale and malodorous. Can anyone suggest an additive that will assist in disinfecting and deodorising the tank.

Thanks,

Mervyn Mitchell

[tkeithlu]

Rule of thumb: Nothing survives bleach. But.... you must use is sparingly in dilute form for longer periods of time or you will damage the SS tank. You can try other disinfectants first - very little survives alcohol in greater than 12% concentration. You've also got a flushing problem - you not only want to kill the stuff, you want to get rid of the corpses. You might start with simple water flushes to reduce the load, then move to disinfectants, then move to water that is drinkable, but tastes of chlorine.

[tkeithlu]

Another way of looking at it. Utility companies predict how much chlorine will be used up between the purification plant and your faucet, so they kill the bugs but leave you with good water for your coffee. They also flush lines that hold unused water for long periods, or which flow too slowly to pass junk through the system - you see them out there opening fire hydrants and giving slow mains a good rinsing out. If they are negligent, you get rusty water for a day or two.

[GordMay]

Greetings and welcome aboard the CF, Mervyn.

See ➥ http://www.practical-sailor.com/issu...k_11230-1.html

[SSgtPitt]

Hydrogen Peroxide. Bleach and stainless steel don't do well together. If you must use bleach, mix it with water before pouring it in the tank.

[a64pilot]

Do you have an inspection port?
If so I'd remove it and get a look at what I had, I'd then start pumping water out there and flush it several times, nice to have a pump you can put into the tank for that. After flushing it out, I'd fill it with city water and possibly, maybe a small amount of chlorine bleach and let it sit at least overnight, then pump it out again and that ought to be all that is required.
I have an aluminum tank myself and am overly paranoid about chlorine so I filter all my water through a charcoal filter as I fill the tank, if I let it sit for a month or more in Summer, I need to flush it out and refill with unfiltered city water, that is enough chlorine to kill whatever is in there that makes the sulfur smell, it apparently takes very little chlorine.
Unfortunately you simply cant get a high enough concentration of Hydrogen peroxide to disinfect, I looked into it as I have that paranoia about chlorine, but I think it was gallons and gallons of hydrogen peroxide needed, way more than was realistic.

[GBonjour]

You can get 35% food grade Hydrogen peroxide. I use it to flush a hot tub. 1 pint will do for hundreds of gallons

[a64pilot]

Originally Posted by GBonjour

You can get 35% food grade Hydrogen peroxide. I use it to flush a hot tub. 1 pint will do for hundreds of gallons

Not doubting you, but where, and reference for quantity needed?
I sure would like to never put chlorine into my tank ever again.
On edit, I found sources to order, now how much is required?

[Cheechako]

Bleach in water, it doesn't have to be in there long and shouldn't effect the metal in that time. Rinse well.

[westwinds]

What causes odor in drinking water tanks is trace organics that decompose with the help of bacteria and use up the oxygen in the water. The water then goes to bacteria that do not need oxygen with strong nasty odors. I would drain the tank, flush tank from a domestic water supply using potassium permanganate in the water.

https://iaspub.epa.gov/tdb/pages/tre...Id=-1644188630
Uses of potassium permanganate in water treatment plants

How to Use Potassium Permanganate in Water Treatment | LIVESTRONG.COM
How to use potassium permanganate

http://es.www.caruscorporation.com/r...et%20final.pdf
Stainless steel compatability

[sailstax]

We have had exceptional success with Puriclean & AquaMega tabs made by Clean Tabs in the UK. Puriclean is a powder specifically designed to clean stainless steel boilers and the aquamega tabs go in with each new tank of water to eliminate any bugs that may be in the water supply.

Practical Sailor gave them top ratings. Neither are cheap but then again neither is a trip to the doctor or ER due to bad water.

[GBonjour]

Hello again Here is a link for calculating different strengths and usages for Hydrogen peroxide. after you have used the stronger mixture, you just flush with fresh water and in lower concentrations, it is non toxic and benificial. I get mine at a health food store.
Hope all goes well with you!

https://www.dirtdoctor.com/garden/Hy...ter_vq4235.htm

[JD-Odyssey]

If you decide to use bleach, just make sure it has no additives. Some companies, like Clorox, are putting additives in to reduce splashing and the labeling is very subtle. Others may add surfactants.

[LooseGoose]

The procedure outlined in Practical Sailor works very well....I use it every start of season myself.

Curing the Tainted Tank - Practical Sailor Print Edition Article

However, there are a few other things you may be able to do to improve your result. First, there will be sediment at the bottom of the tank. I hope you have an accessible drain fitting at the tank bottom. Remove that plug completely to encourage maximum outflow, and drain the tank into the bilge, pumping overboard. Next, if possible, mechanically clean where you can if you have and access point. Then, hit the inside of the tank, especially the bottom, with as much volume and pressure as possible to dislodge sediment sludge, and quickly drain effluent through the drain plug. Next, using any available method to seal a hose or fitting to the bottom drain (just hand pressure worked fine for me), fill a few gallons from the bottom, then let it drain quickly. Repeat until water runs clear.

A final trick to scrub an inaccessible tank bottom is to pick a really lumpy day, take the boat out into a seaway, and dump a bag or two of ice cubes down the filling fixture. The sea-induced boat motion will cause the cubes to run back and forth on the bottom of the tank, scrubbing whatever is left down there into solution....drain quickly. Back in port, prepare and apply the sanitizing method to your now "clean as can reasonably be"....tank, and water distribution plumbing and fixtures. Don't forget the hot water heater.

Cheers

[wrwakefield]

Originally Posted by mervynmitchell

I have bought an Alajuela 33 with stainless a steel water tank in which the water has remained unused for some time (2-3 years) and is stale and malodorous. Can anyone suggest an additive that will assist in disinfecting and deodorising the tank.

Thanks,

Mervyn Mitchell

Mervyn,

We maintain a list of the cleaners, etc. we have found effective.

As other have recommended, first do a thorough cleaning through the clean-out ports [or if you lack ports, a thorough fresh water flushing- I mean days of letting a low flow from a potable water hose run into the tank fill and overflow out the vent...]

For sanitizing/sweetening our stainless water tanks,we use Neutra Sul HP41N Professional Grade Oxidizer [for cleaning/sanitizing potable water tanks and plumbing- similar to 7% hydrogen peroxide]

It is cheap [~US$10/gallon including shipping] and won't corrode your tank or plumbing like bleach will.

I'm specifically recommending against bleach on stainless or aluminum... You can Google for reasons if you want to know more...

Best wishes getting your water potable again.

Cheers!

Bill

PS: Years ago on another smaller boat, I had a 'friend' unintentionally pour gasoline into the potable water tank instead of the fuel tank [Atomic 4 engine...] I didn't discover this until I returned to the boat about a month later... I successfully restored that plastic tank to potable use by flushing with fresh water and treating with a strong hydrogen peroxide- similar to the product I mentioned above... I didn't think that was going to be possible, but it was cheap to try...