I'm telling you...using an aerator pump and any kind of valving will be slow. Changing the valves can't make more than a few minutes difference. With the positive displacement Talullahs, I hit the switch and time 2.5 minutes to get the bags full. Another 2 minutes and your empty. I got tired of having to swim for 30 minutes to wait for the bags to fill...and then talk the family into driving around looking at houses while we waited 30 minutes for the bags to drain. My only regret is that I waited so long to change to Johnson pumps.