I have a standpipe to drain the water in my new tank's overflow box. Naturally, if I use just a straight pipe sticking up it is very noisy. From what I understand, if you connect an upside down "U" shaped pipe to your standpipe and have a small tube sticking out from the top of the upside down "U" it should get rid of the noise. I tried this, but when I put the "U" on, my tank could no longer drain enough water to account for the water being pumped into the tank. The "U" has a wider circumference than the standpipe, so I don't know why this is restricting water flow. What's the trick to this?