I might also put a layer of rubber sheet between the plywood and acrylic.
The intent of using an acrylic sheet is to have a very flat but more compliant layer under the glass floor
That's off-topic here but the whole point is to be able to walk into the tank safely. I'd assumed that the real floor was solid enough, but better to ask.
Then, if it is, I need a raised stool to stand on to do work mid-tank.