I love the minimalist style the Coop's racks. So I set out to do a similar setup, and it's coming together well. I planned on doing a couple 55 gallon tanks mixed with 20 gallon ones since they are the same width. Now that the $1 sale has started, I looked at my local Petco, and they have no 55s right now, but there were 75s. So now I'm thinking about the added width/weight. Cory has said the weight with glass tanks are carried on the corners. I think if I use thicker or two bolts at each corner it'd be alright. An alternative would be to double up the vertical 2x4s. Thoughts?