[zaroba]

how is the false bottom being made? does it even need glue? if your using pieces of pvc pipe to hold up egg crate, you might not even need anything to hold it together. might be able to just stand the pipe where its needed and lay the egg crate on top. it would depend on the diameter of the pipe and whether or not you plan on moving the tank though.

i used hot glue in my large viv on the stream i used to have that was made of several pieces of plastic. had mixed results with it. it did work for a while, and a drop of it that fell in the middle of it never came off despite constantly being under water, but some of the glue that was holding the pieces together weakened and caused leaks. might depend on the glue itself though.

main problem i see with hot glue is that it isn't flexible like silicon. so if you use it on a false bottom and don't equally support the weight anytime its being handled, any bending/twisting of it could make the glue fail.