/diy/ - Do It Yourself

>>1391812
Since this is really the only woodworking thread I see and I bought the lumber at Home Depot I will post here...
I recently made a rack for 3 20 gallon tanks for my fish room out of 2x4s. I bought the lumber at Home Depot, which is just KD whitewood studs. Made all the measurements and cuts at home with my Granspa's old circular saw. I pretty much fucked up because a lot of my cuts were off by a tiny amount, maybe 1/16th or 1/8th at the most, and a lot of my cuts weren't straight. Anyways, I put the rack together and it wobbled, so I put some leveling feet on it. Went to test it out after I leveled it with an empty 20 gallon tank and the tank wobbled. I tried it on the other two shelves and they wobble too. They all wobble from the same position, the back left and front right corners. I went to Home Depot and got a piece of plywood cut to fit my rack and they fit fine, but when I put the plywood on there, the tank still wobbled. WTF? What can I do to fix this?
>pic related, the tank on the top shelf without the plywood