From my experience with galvanized tanks and epoxy though (even with acid etching etc.) the epoxy eventually deteriorates somewhere and allows water underneath it. You're better off sticking with plastic or fiberglass if you have a choice.
You didn't get what I told you to get.
The epoxy I pointed out is commonly used at waste water treatment facilities submerged in the poo poo tanks, and is guaranteed for 20 years in such service if properly applied and cured.
It's best if ya don't have to mess with the stuff tho. A novice can screw it up pretty bad!
That's the kicker. It's not easy getting something to stick to galvanizing, not easy at all.
can screw it up pretty bad! 
