I also have the Squirt set up as a close-loop, and the sump makes no difference with how I plumbed it. The bypass is hooked up to a Tee that is attached to the pump's outet. Then the bypass just goes back to the main tank. So essentially the pump goes to 5 outputs stationed at various points in the tank, 4 going through the Squirt and 1 through from the bypass. Good luck with either the Squirt or Super Squirt. You should be happy with either product.