I finally fired up my 90g wet/dry tonight to replace the FX5 on my 230g tank. This is my first sump, so I am not too sure how to troubleshoot problems. I have a bypass back into my filter sock which basically just cycles the sump. Everything works great with the main tank shut off and that cycle running. When I switched valves to open the main tank, I initially got the toilet bowl suctioning as the drainpipe would start to siphon. I opened the hole on the end cap. That helped with the siphoning, but now the pump was drawing down the last chamber in the wet/dry and sucking in air which caused problems. After opening up the hole and adding some water, things are better but not 100%. I built my Durso pipe a little shorter in the overflow box than I would have liked, but the noise is not bad and its only about a 5" drop to the elbow in the Durso. The water level, however, is staying constant up near the top of the end cap, occasionally overflowing the cap. I am also getting a lot of bubbles in my filter sock from the drain pipe. The hole is at 11/32" on the end cap right now. I thought that sounded a bit large, and I was starting to get a sucking sound until I added more water. If I put my finger partially over the hole it starts to siphon fairly quick though. I'm running a Dart pump. Thanks for any feedback. Its in the garage and not really that noisy, but I think I can make it more or less silent if I can sort this problem
