So I just bought a ne used 90gallon tank it came with sand on the bottom, I'm going bare bottom so I took the sand out I found what appears to be a euro board bottom. Is a 2 in glass rim around the bottom glued down. So is this common maybe in older tanks? And any advantages?
full tank shot, from that pic you provided it looks like a someone drilled the bottom and made an overflow box. older tanks did not have tempered bottoms and this was possible, the newer tanks have tempered bottoms and you can't drill them