I have the 220 and i broke it in by bringing the water level right to the bottom rim of the collection cup cone. Just high enough so u can see the micobubbles in the tube. The super skimmers r very sensative so if your water is slightly unstable or if you are feeding or adding any addatives to the water the level in the skimmer will fluctuate greatly. You really have to keep an eye on it while it is breaking in. Mine took almost 4 days to break in and start making good foam instead of the 24-48 hours suggested by the manual. I am very pleased with mine, hopefully you will be with yours also. After the breakin period i rasied the water level in the skimmer so that the water was about 50% up the cone in the collection cup and that gave me good dry foam. But for breaking it in i would suggest making the water level just high enough to reach the collection cup cone. During this time you probably wont get any skimmate so dont expect it, but the unit needs to break in just by running water through it for a few days.