When people say they put a mat under the tank to account for the base not being perfectly level, do they really mean flat? The two are different and I just wanted to be sure. I’m planning to set up a tank on a countertop that should be level but may not be exactly. I was going to use a mat to account for irregularities but if being level is the true issue, I would also have to use a sheet of something like plywood that I could shim as necessary.
Also, does a rimless tank need full support on the bottom or can it just be edge supported like on a rimmed tank? I was going make a small stand for a 12 gallon long and was wondering if it needed a “top”.