I had a question about these shelving units. Edsal 60 in. H x 36 in. W x 18 in. D 4-Shelf Steel Commercial Shelving Unit in Gray-UR361860 - The Home Depot Or Shop Style Selections 53-in H x 35.7-in W x 14-in D 4-Tier Steel Freestanding Shelving Unit at Lowes.com My room doesn't have much space to work with for putting tanks up and the dimensions of these shelving units would fit perfectly on one of my walls next to my desk. I was wondering if anyone has tried to use one of these types of racks and would they be able to hold a 20 and a 15 gallon tank?