See if you can find used $10 10 gal tanks... I have a 10 gal that Chris at FishScales drilled for me. First one cracked, second was perfect. When you punch through the glass a the end that is the critical part! Dont have hardly any pressure on the drill and be ready to yank back up as soon as you feel it go through. I do not think any 10 gal are tempered on the bottom, but I could be wrong.