I have a question for an alternate mod. Can the top be left off and just put the valve on the stock tubing? I tried and the noise cut down considerably but I can't tell if it's not long enough a trial to see if it works. I have the in tank cup, and it fits directly over the outlet with the top removed. I bought this to upgrade from the aquatic life 115, and it's been a disappointment so far. Continual adjustment of 1/8 to 1/4 turn then wait a day to see if it worked? I've had this thing up for a month, still just able to get watery skim when it works at all. The other skimmer made foam with nearly no tinkering within 15 minutes the first day, no break in. Not sure in retrospect why I gave up on it. Just thought I could do better.