I have an AquaMaxx Cone S-CO3 in sump skimmer, which sits in a 40 gal sump filled with about 20-25 gallons of water. The skimmer is overkill for my newly set up 180 gal FOWLR tank but the skimmer size was suggested by the sales rep because of my messy puffer; however, I no longer have the puffer, and I have yet to get the skimmer to settle down. I started stocking the tank two weeks ago, even though the skimmer would not stop overflowing. It continues to overflow back into the sump so much so that the water in my sump looks like a skimmer cup with a head of dirty foam about an inch thick! The skimmer is still running wide open and it's been running wide open since mid December. I have raised and lowered the height of the skimmer multiple times to no avail. Supposedly, the sweet spot or height is 7-8", but not in my case. I'm not supposed to run the skimmer in less than 7" of water or risk damage to the pump, yet the skimmer only stops over skimming when I lift it to about 5" in the water. How do I get the skimmer to stop overflowing? BTW, the skimmer was purchased new but is the older version with the pump attached by hose outside the unit, not in the belly of the unit. I know water changes can help, and I have tried that fix. I know additives such as water conditioners and medicines can cause excessive skimming, but after adding chemicals, the skimmer should settle down in a few days to several weeks. It's been two months, and I have seen no slowing down. Am I too impatient, or is there something else I can try? I read good things about this skimmer...researching quite a bit before buying. I'm very frustrated with this skimmer so far. None of my other tanks have this problem and I have different brand skimmers on each of my tanks-all purchased new. Suggestions? PLEASE...if anyone has tried anything different that I haven't tried yet...please share! I'm desperate. I can't afford to buy another skimmer and I can't send this one back. I've had it too long. I don't know if stocking makes a difference, but in case you need the info to help, my stock in the 180g tank is a hoeven's wrasse, cleaner wrasse, dragon wrasse, ruby head wrasse, yellow tang, kole tang, vagabond butterfly, mystery goby, two engineer gobys, and a flame hawkfish. All fish are under 3-1/2" except the hoeven, vagabond, and yellow tang, which are all about 4". I also have 7 tubo and 7 cerith snails in the tank (though I may have a few less cerith snails today as I saw the baby dragon wrasse trying to eat one of them a few days ago, but I expected this wrasse behavior).