In-Sump Media Reactor for Aquariums
This reactor is designed to hold PhosGuard or similar media and sit submerged within your sump.
The opening at the top accepts 1/2" OD vinyl tubing snugly for a water supply (you can use 1/2" ID by using a short length of 1/2" OD as a coupler.)
The design pushes the water all the way to the bottom, then out the top through your media, ensuring maximum contact.