I've got 1 inch for the bottom, back and side. 3/4 for the 2 sidesWhat size tank and how old is it? A few years ago I almost ordered one with them, I saw a few say their sump was coming apart from them but otherwise seems good. I’ve basically narrowed to them and glass cages, which I’m leaning real hard on just seeing the activity in the group from years, and prompt communication. Always like to hear as much from the relevant audience if possible.