There are actually 3 pumps. The protein skimmer has a pump delivering 3:1 water to air ratio (80 gph air & 240 gph water). There are then 2 circulation pumps. One drives water through the filter system and one pulls water from the skimmer chamber, giving total circulation of 960gph. Both have bubble traps to ensure microbubbles are minimised. We'll have a video on
www.redseamax.com shortly, showing the complete system. In the meantime there's a low res short video we took at a show. At least you can see the water flow from the pumps.
http://uk.youtube.com/watch?v=1R8knkhEzdg