Ya ya, some use just strait water but I know. you get the idea. Lol. Aluminum does not rust will last for a long time. Brass would be best and last forever. I would do it if I had hot lights.
I've thought about this in the past. Really the best way, and the only way to avoid corrosion issues or poisoning the tank with metals is stainless. It's very expensive and it's hard to work with but it really is the best for this. It's heat conductivity isn't as good as other metals but corrosion is always going to be an issue otherwise.
Understand that fluoride will allow aluminum to pass through the blood brain barrier .By using the right bottled water one can eliminate the concentration, and general mental functioning together with a general foggy .