Most Extreme 300 and MSX 300 users either run a BB5000 and a BB3000 or a BB5000 and a PSK2500, 1000. Both will need an output adapter to mate the pump with the skimmer. The adapters can be chosen through the drop down under the Extreme 300. http://www.coralvue.com/reef-octopus-bubble-blaster-5000-skimmer-pump