As smatter said, the 9010 cannot run with the full air flow, it will skim pretty much just water at this setting. The cup is also the reaction chamber so the 9015 has more contact time and more air flow as a result of the cup. It skims very dry and the 9020 foam extractor is a better upgrade as it is about 3/4" shorter and this allows a wider range of adjustment. With the new models 9011 and 9016 the 9016 will likely have a slightly longer impeller and slightly shorter cup to improve the performance. Also, keep in mind the stated ratings are essentially for FOWLR tanks, the manuals and catalog recommend reducing the rating by 20% for soft corals, 40% for mixed reef, 60% for SPS and 70% for SPS with a high fish load.