I am looking at building a stand for my sump (it will not be under my tank but to the left). Sump without reservoir is 72x24x15, so max gallons are 112 if about to overflow or regular max weight of 80G when there is a power failure so with weight of sump, it's about 1K pounds when the power goes out or close to that with the return pump off. If I use standard 3030 (3") I can get the deflection rate to 0.07. The span is 72 inches with the top support resting on the support columns. What I have read is you should keep the deflection less than 1/10th of an inch. The height is 24 inches with 2 72" beams and 6 cross supports. I ran a calculation where I inserted a center support and stepped it down to 2020 (2") the deflection was .35 and the same with 40-4040 and the deflection was roughly the same. I just feel like I could park a sherman tank on this. Anyone who built their own tslot do the calculations? If so what did you wind up with using and if you are in the .30+ range, can you tell? BTW - I am not an engineer. I am building a lighting rack out of Tslot and said well, I might as well match my sump stand and well you know how this story goes...