Aquarium stand bowing in the center

[Sharkbait19]

Hello,
Admittedly, finding a stand for my Fluval 13.5 was a bit of a rushed job, so I wound up getting a stand much larger than the tank itself. Unfortunately, my concerns are coming true, and the stand is beginning to bow in the center under the tank’s weight. Would I be able to fix this by putting a sheet of plywood between the top of the stand and the tank, or do I need to do more to redistribute the support to the stand’s four corners?
Thanks!

 

[The_Paradox]

Better solution and cleaner looking would be sister up a piece of 3/4” ply underneath. Run it as close to edge to edge as you can then glue and screw with 1” screws.

 

[MrGisonni]

And.....2x4 on its edge under the plywood if space allows

 

[tedfisher496]

Pressboard can not support the weight of this aquarium. You can modify it or build a new one.