I am having the exact same problem. I have had it about a year and it worked fine and I noticed it wasn't skimming well anymore and I took it apart and cleaned it, took out the screw and brushed up and down that hole with a small
brush, this was 2 nites ago and it shows no sign of skimming at all. I have the
Maxijet 1200 pump with it and the preskimmer box. I am thinking of going another route. I have a 36 gal sw
tank. I have a seaclone 100 on my small
20 g QT which has turned in to just another tank heaven forbid anyone gets sick --and it is skimming fine. I'm about to think that they work the best for me.