Thanks Johnny, that's very informative! I will definitely keep this info in mind when planning more involved vivarium builds (oh yes, there will be more ). For this time, since I'm just doing the drain pipe, I will look for the matte black acrylic primer you mentioned earlier. I've ordered a 10-gal aquarium with screen lid from Wal-mart ($25 including shipping, and the reviews are all positive!) to use as a temporary habitat if we end up with froglets. I have a very strong feeling that at some point in the future that will become an aquaterrarium for fire bellied toads, and I'd love to do some "viviscaping" at that point.