@Joe Glass Cages and his team built mine. It was a customer idea I had for years and Joe was able to make it happen.Hey I love it!
I had one just like it years ago! I divided the 40 breeder the long ways with black acrylic and then added more divides in the back so I could run any filtration or just have a return pump spot, etc...
Is yours kind of the same idea? I see an egg crate spot.
This was my sump... it had a small cut out right and left for the water to flow in and out to the hidden chambers. I lit it with two t5's.
Just enough room for the skimmer and return.