They will bend again pretty quickly as aluminum and some other metals like to go back to their original shape. It is a thin piece, So I would suggest you do my process below before it does it again.
I use Epoxy or 700 oF silicone gasket sealer from Napa( Black Material) and I use that to glue a 1/8" thick aluminum plate to the inside of the Platform . Then,I use a 6 inch wide Flat belt sander and sand it flat in about 5 minutes.
Even with the reinforcement about every 3 to 4 months, I have to run it on the belt sander again...
I have pictures up here on the forum on how I clamped the Platform to a heavy flat aluminum plate with the Thin plate inside the platform . Heat cured the Silicone Or epoxy in my oven in 2 hrs at 300 oF.
You don't want thicker then 1/8th alum.or it will get in the way of the Liquid going back and forth across the inside of the platform. I know that from experience! I machined a thicker one from scratch and had problems.