I'm using fiberglass screen on the top of my tank to help it breathe a little better and keep it cooler. I want to close off my skimmer outlet too. Is the fiberglass screen ok to use under water or should I use something else. I was thinking of buying one of those green fish nets and cutting the netting out and using that, but I already have the screening so if that'll work it would be cheaper. Do you think I should seal it on with sealent or just rubberband it on?