I have to drill a 45mm hole for a one inch bulkhead through 3/8" glass for the return in my new growout tank. I want to put the return as high as possible how close to the top edge can it be?
Just shooting from the hip here, but I think I wouldn't get closer than 3-inches to the edge to maintain structural integrity. I think my 50 gallon was drilled at about 3-inches.
I agree with Jim. Any reason you can't just go over the top?
I want the clean look of all the plumbing in the glass. I have drilled tanks within 2" with no problem. This tank is 3/8" glass and only 10" of water no real pressure it could be a third that thickness. I was hopeing to go within 1 1/2 ".
Well I have talked to people on other forums and several professional tank builders and they all say 1.5" is as good as 3" and 1" should be fine. I will be going with 1.5" and will keep posted.