I have a a rack system set up that currently has a 55 gallon aquarium set up on it in the middle and two 10's and a 20 on the top (https://www.homedepot.com/p/Husky-4...-W-x-78-in-H-x-24-in-D-N2W772478W4B/319132737). I am looking at upgrading to a 90 gallon glass framed tank and was wanting to add some more support for the weight as the existing shelves are a little flimsy in the middle. I am thinking about getting a sheet of 3/4 plywood and putting it below the tank but I'm not sure if that would be overkill. Alternatively I was also thinking about cutting some 2x4s 24 inches long and running them front to back to distribute the weight to the beams. Any ideas or recommendations?