I insert tubing into the opening on the rubbermaid cup lid,and attach that tubing to the fitting for the water pump. It works pretty good, Mind you,I already had the rubbermaid cup, foam,polyfil,and tubing. so it was much cheaper for me. I only needed to spend the 18$ for the pump,which has been running for 2 years now.I had it in my 125 as a supplemental filter. Simply a backup in case any of my 2 canisters went down.