what woukd be a good clamp to go on a 90 gallon tank on top that would be pretty close to flush with top so my light won't be raised in the middle? It doesn't have a center brace it bows a bit. I don't know which clamp to buy any recommendations? And if I drain it to about 15% full and the just get the clamp tight with it at that level and fill it back up that be fine the top is 18" deep thanks