I just got two zoo med UTH off of a buddy of mine for my 25 gallon tank and i was wondering if i should use both? One is a 4x7 and the other is 6x8. Also the 6x8 pad doesnt have any adhesive material left on it. Any suggestions of how secure to bottom of glass? I was thinking foil tape?

Also what is the best way to keep the humidity at a constant level without effecting breathing air?

all help is appreciated thanks in advance!

-Kevin