If they are acrylic tanks you can use a hole saw to cut them for the bulkhead. Gravity feed is fine above your sump or tank. Pods don't die from going through the return pump,( agains popular belief). You can use one of your drain lines to feed the fuge or pump the water up from the sump. At least 20 watts of light are needed, but 55w- 96w PC's work ell for this. If you run the light 24 hours it will grom like crazy, but most people like to run it on a lunar cycle to help keep the PH and 02 up in the night.