What kind of paint for interior of stand?

[builderguy]

I want to paint the stand I'm building for my tank with something to waterproof it.

What should I use?

[Medicoles]

Multiple coats of Kilz #2 works well

[Perched Urchin]

Spar eurethane is good - it is the same stuff you use on wooden boat decks.
Multiple coats of Kilz as mentioned works too. If you want it a color, I believe most places will tint for you, or you could even do a coat or 2 of coats of Kilz then a coat or 2 of exterior latex.