FYI, 2'x4'x1/2" PVC sheet from Home Depot
Just trying to be helpful....
For a home improvement project (capping exterior wood windows), I found this product at Home Depot ie: sheets of cellular PVC. I assume it would be safe in aquarium, my guess it is the same PVC they use in non-pressure (sewer lines) pipe.
This is cellular PVC ie: it will float and has little structural strength. If building a sump with this stuff, I would include external support (3/4" plywood) just in case.
You can use regular heavy duty PVC cement but you still have to work quickly, it will set quickly. I would not use regular PVC cement. There is another product, Christys Red Hot White Adhesive, which cure much more slowly but I have not used it.
Some YouTube channels claim that Krylon Fusion spray paint is safe for aquarium use, not sure if this is true. If so, this would be a viable option internal device such as overflow boxes ie: paint them black. You can also use petroleum dyes mix with clear pipe cleaner but once again, no clue if this is safe for aquarium. From my personal experience, using dyes on PVC pipe is a pain in the a.., the color are very inconsistent.
If I setup a second tank, African Cichlids, I may use this stuff for a support system to create a rock wall ie: Mbuna Condo's! I may use it to create a shelves on my planted tank.
Issues for me, how to glue on gravel/sand to the PVC for blending in? Just cover it with silicon glue and toss on the sand or gravel? Can Gorilla Glue, a polyurethane glue, be used in a tank?
Acrylic is great stuff but expensive and in short supply with the COVID-19 pandemic . Anyways, pricing info...
4'x8'x1/2" $78 Note: this size has a texture on one side.