That thing looks great until there is an earthquake, then I worry. Even with those gussets in the drawing, the lack of sheer supports look like a problem.
140G tank = 1200 pounds.
Even a moderate earthquake can generate 0.2G horizontal acceleration.
That means 240 pounds of side force. Not gigantic, but with no real sheer supports, a problem.
You can test it.
Put the back legs against the fireplace.
Have two strong people push horizontally against the top rail. Does it bend?
As it stands,yes. But it’s missing the gusset. We over killed it with gussets. It didn’t ship for some odd reasons. Gusset will sheer it up. There will also be wood dividers inside the cabinet. The divider is going to divide the storage from sump.I will also have divider to hold the electronics.