Did you replace/reinforce the shelf ? It looked like a plastic (not wood) material, but probably not thick enough.I have a local Costco that I get mine from. In addition to the other solid suggestions, I thought I'd mention them as well. Also have them in that $50-60 range.
I have done both - used their shelving that came with it and put in my own plywood. Since I am not going so high - I keep mine at 36" max, I just use two of their shelves per level, and have one left over. On some others, I had extra plywood from another project and just cut to fit. The Whalen system is the one that I have been getting.Did you replace/reinforce the shelf ? It looked like a plastic (not wood) material, but probably not thick enough.
I think some costco locations carry this lower priced unit, and some have a different option that costs more.
There is also heavy-duty wire shelving that doesn't need a board at all, although you could add a thin one if you like the look or want to ensure a solid/smooth surface under the tank. Different brands I've found are Whitmor, Seville Classics, Metro ... Walmart search results, Whitmor heavy duty shelving.
Just fyi, a useful chart of common tank sizes and filled weight. The weights appear to count the tank and water but not substrate, equipment, etc.
At the moment just the one listed in my signature. I'll be buying more at a later date.How many tanks are you looking to support? I bought a bronze baker's rack from Hobby Lobby for like $70. They had a couple of different sizes, but the one I got has four shelves. The top shelf is a little shallower. I currently have two 10G shrimp tanks, two 2.5G Opae Ula tanks, and two 3 - 4 G vases on the top shelf.
It is a folding rack, so I'm slightly worried about the stability of the shelves. They seem to be holding up well, but I'm considering adding some kind of cross bar and clamps just to make sure nothing falls.
Your racks are something like I want. At the moment I just have the tanks in my signature but I always have my eyes open for good deals. I'm wanting a few 10g's