Ok, I'm looking to set up my Exo Terra 18x18x24 to hold a few inches of water, but I want to be able to drain this out twice a week. So I was thinking I can have a hole cut in the bottom, attach a bulkhead fitting with a ball valve. I'm not quite sure how these items are threaded, but in my mind it works. I'm looking to see if any one else has done this, and the best placement of the hole. The stand for the viv is open on the bottom, it does have a support board in center.