Aluminum tank maintenance: bleach, alternative, or nothing at all?

[denverd0n]

Bleach and aluminum IS an issue. It should not just be ignored. But it should not be over-exaggerated, either.

If you dose your aluminum tanks with large amounts of bleach every time you fill them you WILL eventually have problems. If, on the other hand, you use moderate amounts of bleach, no more than once a year, to clean and sanitize them, they will be fine.

So what is a moderate amount of bleach? One quarter of a cup, of normal household bleach, per every five gallons of water is all you need for sanitizing all but the very worst of tanks. It should be sloshed around in the tank for no more than an hour or so (a half hour is actually PLENTY of time), and then rinsed out. Higher concentrations, or longer soak times, are not necessary, and will only serve to damage your aluminum tank.

This is very definitely NOT a case where "if a little is good, a lot must be better!"

If your tank is so dirty that the above is not enough to make it clean and safe for drinking water, then you have let it go WAAAAAY too long! In that case, it's time to forget the bleach, open it up, and power-wash the interior!

[OrangeCrush]

Thanks for the input, all. Based on my very clean tank water last season and a healthy dose of chlorine in NYC drinking water anyway, I'm going to go with the 'if it aint broke' school of thought for now. I will consider the unfiltered city water I put in there already to be my "shock" treatment, however meager, and I will start using an in-line hose filter to fill my tanks for the rest of the season.

I'm sure that it's true that the corrosion from a quick purification is negligible and might take decades to manifest itself, but 'decades' is what I hope to get out of this boat. Thanks again.

[sck5]

I believe I first read that this was a good idea in something Peggy Hall wrote - but the gist of it was that chlorine is bad over the long term but not for a short period of time. That is, you can safely shock your tank once a season if you then rinse it out again. That is what I do - when the boat comes off the hard it gets a shock treatment of a healthy dose of chlorine to sanitize the tanks and pipes. After that I just fill the tanks with water out of the hose and it seems to work just fine.