Holes in the bottom for a tank that size is asking for trouble. Do you ordered the holes drilled or AGA suggested that? They will drill holes at the bottom if asked because people do request that for reptile tanks. I have an AGA reptile tank with custom drilled hole at the bottom. They did a very nice job to drill the hole in my tank and the bottom is NOT tempered. Are you sure the bottom of your tank is tempered? If yes, it will have a sticker saying "tempered glass, do not drill".