I bought a 5.5 gallon tank today, and took the black rim off.
When I filled it with water I measured how much it bowed and when it was half full the glass in the center bowed by 1/8th of an inch. When the tank was full, I measured the bow again and it was at 1/4 of an inch. Is this safe to use? I left the bottom rim on to give it a little more strength. The brand of aquarium is Aqueon (or something like that, bought at petco)