I've been keeping a watch on it and kept wondering how I could keep air out of the U-tube. The water splashing in the overflow box created bubbles which would get stuck in the U-tube. I started to become irrated with this like everyone else. I kept messing around around and figured if the U-tube was set just half an inch higher, it would suck more water. I set a sharpie for now under the U-tube to have it set a bit higher. So I began fiddling with it for about 20 minutes and ended up tilting my overflow box in the tank at an angle so more water could flow into it with out creating any bubbles. Over 24 hours later, not a single bubble in my U-tube. I tried keeping the overflow box in the tank level but couldn't get working as well as if it was tilted. It seems like it's working at full capacity now and 3 times better if not more than before. Ever since, my mushrooms have been popping out more and my anemone his bigger and there's more shimmering in my tank.