I continue to have problems keeping air out of the U-Tube in my overflow box. I finally discovered a way to get it going again without sucking the air out with my mouth. *yuck* I put the entire tube into the tank and moved it around to fill it with water yet get rid of any air bubbles. Then I filled two paper cups with tank water and put them over the ends of the tube so that I could lift it out of the water without losing suction. Keeping the cups on the ends, I put the tube back in the overflow box and carefully removed the cups. It seemed to work great and the water was really flowing again. Unfortunately, this only lasted for about three days before there was air in the tube again.