This one is for a 20gal grow out.Hello, I see no problems using cinder block. For support on tank I used 2x4 set up like flooring joists.
The first pic is for a 55gal. I removed center blocks cause it was overkill.
The 2nd pic is a 90gal & the design held perfectly.
On a 7ft tank I would do 3 sets stacked brick. The setup only took a few hrs to make & another hr to paint. Hope this helps!!!!! View attachment 320224View attachment 320225
Youd be crazy to put that much tank on anything not build to survive an earthquake
It's all cohesiveStands are solid, I would worry more about floor!!!!!
In that case you could get away with the block. 3 rows with 2x12 on top.It's a concrete floor. So it can hold a lot of weight