go to home depot/lowes, they sell 4x8 sheets of foam. theres usually white, pink and blue foamboard. ive always used 3/4" thick white, and its around $10.
Finalfire9;2911980; said:That fish room looks like my place haha! Chairs and fish tanks everywhere

Donny417;2911722; said:Fill it in with JB Weld, and face that side of the tank towards the wall. JB Weld will fix anything, even says so on the label.