Sterilizing Aluminum Water Tanks

[Steve Swann]

What is the chemical treatment recommendation for sterilizing 200 gallons of water in aluminum tanks that doesn't affect the aluminum? I want to sterilize for bacteria, cysts, larvae, algae, and other waterborne bad guys - and for now, I still want my crew to survive the poisoning.

Thoughts and recommendations?

Steve S.

[sv_pelagia]

Most will write NOT chlorine, although it is not clear how much harm, if any, occurs with a single shock treatment, followed by emptying tank and refilling with clean non-chlorinated water (e. g., charcoal filtered).

Hydrogen Peroxide is NOT a solution.

One certain fix is to put a suitable filter system (<1micron, usually multiple filters in series) into system after tanks, perhaps with a separate tap so clean drinking water can be had (water for cooking, dishwashing, showers etc need not be filtered). Filter system could also include a 12v UV system.

Once your tanks are clean, you can filter (and possibly UV light) BEFORE as you fill tank. There are several systems available (e.g., WaterFixer: https://waterfixercompany.com/ )

Question: do you know your water tanks are contaminated?

[Steve Swann]

Thank you for the reply.

My tanks are starting to get a trace of algae in them since we are in the tropics. We put the boat up for the next month for the holidays and returning mid January. There is some water remaining in the tanks, but they are by no means full. I want to shock them to ensure they are clean. I also do not want to put any chlorine in them since we have a watermaker that uses one of our saddle tanks for back flushing, and this particular tank is notoriously difficult to empty completely. As an aside, it would be exceedingly difficult to reroute watermaker lines and separate to the sink, just one tank for drinking water in my maze of tanks

I do have a good charcoal and ph filtration system and adding a UV sterilizing feature is economically and logistically feasible except for my ability to recirculate what is already in the tanks. And, this combination isn't very effective against algae growth.

So, back to my original question, what is a broad spectrum additive for aluminum drinking water tanks that kills bugs and algae ?

[HopCar]

This is what you need. Won’t hurt aluminum. Works great.
https://www.cleantabs.co.uk/puriclean.php

[Bill O]

Originally Posted by HopCar

This is what you need. Won’t hurt aluminum. Works great.
https://www.cleantabs.co.uk/puriclean.php

The active ingredient in Puriclean is chloride dioxide. Based on this paper it attacks plastic as well as metals and don't think I would use it on aluminum.

[S/V Illusion]

Originally Posted by sv_pelagia

Most will write NOT chlorine, although it is not clear how much harm, if any, occurs with a single shock treatment, followed by emptying tank and refilling with clean non-chlorinated water (e. g., charcoal filtered).

Hydrogen Peroxide is NOT a solution.

?

Actually, hydrogen peroxide is a more effective, less damaging and more persistent disinfectant than hypochlorite solutions. It does, however, need to be the proper concentration just as Cl does - the ubiquitous drug store variety is not an option - you need to obtain 20% concentration peroxide from a chemical formulator commonly found in any large city.


A one-time chlorine treatment provides no long term protection unless you maintain a reasonable Cl residual in the tank. Parenthetically, it isnt the shock treatment which can damage aluminum tanks but rather the necessity to maintain a minimum Cl residual concentration over the long term which is the problem.

[Virginia Lee]

I read in a forum post long ago (1-2 years?) about using colloidal silver. I purchased it and will try it when we go off soon. PM me if you don't find the post. I know I either bookmarked it or saved a pdf on amount to use.

[Captain Puget]

Hydrogen peroxide works in aluminum tanks, not sure why the previous poster says not to use it.

But I agree with a good filter on your drinking water tap (3m makes some good ones).

[sv_pelagia]

Originally Posted by Captain Puget

Hydrogen peroxide works in aluminum tanks, not sure why the previous poster says not to use it.

The US CDC states the following:
Several other common products, including hydrogen peroxide, citrus juice, and potassium permanganate, have antibacterial effects in water and are marketed in commercial products for travelers. None have sufficient data to recommend them for primary water disinfection at low doses in the field.
https://wwwnc.cdc.gov/travel/yellowb...r-disinfection

Water tanks on a boat are somewhere between disinfection in low doses vs large-scale water treatment (for which there are H2O2 systems). Given the above warning and the issues with H2O2 (toxicity; corrosive actions, etc), I stay away from it, even though I have aluminum water tanks.

[GordMay]

Greetings and welcome aboard the CF, Steve S.