Right now i have two tanks set up in an L shape against a wall so that you can see both tanks clearly but there is lots of room behind them for maintnace. so the trashcan will sit behind those. Both tanks are empty right now, but i will be filling them up soon. My ultimate plan is to have both tanks drain into the trash can and pump into their tanks so i turn a 40 gallon and a 50 gallon tank into a 120 gallong tank so to speak. I have a fluval 304 for the 40 gallon and a fluval 404 for the 50 gallon. both of those will be running with about 20 lbs of LR in the 50 gallon (my brother is cheap) and i will end up with about 65 lbs of LR in the 40 (i'm not so cheap and want to keep some corals) I will do a test run to see if the two heaters that are in the tanks will be enough to keep the water the correct temperature without putting too much stress on teh heaters. I also have a seaclone protein skimmer on the back of the 50 gallon tank.
As for the calurpa, will i need to set up a light over the trashcan for it? I plan to keep the lid on so i don't lose much water to evaporation, and also to keep debris out. But i could easily cut a hole in the lid to fix a light to it.