I do domestic chlorination and sterilizations for a living, and maybe I can add some thoughts:
- use of carbon filters is a double-edged sword - they take out organics (pesticides, odor
, etc.), but also take out chlorine. Anything downstream of the carbon filter, is then susceptible to growth of bacteria. Personally, I'd rather have the chlorine than the bacteria.
- the 0.5 ppm of chlorine found in most city waters will not harm your aluminum tanks - it's not strong enough to corrode and it's not very stable - within an hour or so, it's dissipated to nothing, but during that hour, it can kill some bacteria.
- peroxide is what I'd use for aluminum tanks (and plastic for that matter), but the "recommended" dosages that have been posted are great rules of thumb, but there are WAY too many factors involved to use those and be guaranteed of a good sterilization. For example, if you have existing slime (bacteria/mud/organics), you'd need more. If your water is warm, you'd need more. If you have plastic tanks, you'd need more, etc.
- the absolute BEST way to do a sterilization (in my opinion) is as follows:
1. clean the tanks as best you can to remove sediment/slime/mud. Peroxide or bleach cannot kill into any significant "depth" of slime.
2. Add enough peroxide to achieve 20 to 50 ppm (1 ppm = 1 mg/l) of peroxide for 4 hours. You'll probably need to add more during this 4 hour period. Make sure the water flows to all fixtures during this sterilization. Run water to each fixture often - maybe every 30 minutes.
(you are going to need a test kit to verify this level of peroxide. The peroxide is going to be used up as it kills things. I use Hach model 2291700 peroxide test kit. This is important - it verifies that you have a lethal dosage of peroxide for the entire 4 hours.)
3. After the procedure, drain the water tanks to remove dead bacteria/organics and refill with fresh water. If the fresh water is chlorinated, then it's fine. If not, add enough peroxide to get to 5-20 ppm again, and leave it. It's good to go. The peroxide will be gone in a few hours.
I'm sure I should have some disclaimer that if you have 100 lbs of ebola virus hiding our in your water tanks, then you can't sue me if you die. Furthermore, this is no guarantee that there are no "bugs" left in the system. Your local state has a lab that can test for all sorts of bacteria for a reasonable cost.
This procedure also assumes that you might be cruising out there in the wild blue yonder and can't afford to have some bacterial infection. In our camper, I just add a calculated amount of bleach and run it to the faucet and let it sit for 2 hours. If I get some weird bug while camping, I'm not more than 3 hours from a hospital!