Sometimes I vacuum and plenty of debris winds up in the skimmer sock when finished. Other times practically nothing! I do the same process every time (submerge vachead and hose, fill hose with water from eye, keep hose end in water as I attach to vacuum/skimmer adapter, begin vacuuming.) I thought that if I didn't see the debris cloud up as I brushed over it that it was being sucked up. But that's not always the case. I even try to just lift the vachead over the debris spots and just press down to avoid having the brush spread the debris. But there are still times I vacuum for for a half hour only to get nothing in the sock! My question is, how can I tell that the vacuum is actually cleaning while I work? Secondary question, If I hear the pump water flow interrupt while working (it makes an oscillating sound) did I lose suction and should I start over? Thanks for the help!