Let me start from the beginning. I bought my 65 gal. Used from somebody and the guy had a ETSS sump setup witha ETSS reef devil skimmer. He originally had a mag 18 driving both. There was a tee on the return so half of the return water drove the skimmer and half went back to the tank. I did want this setup and put the mag 18 just for my return and put a rio 1700 in just to drive my skimmer. At the ETSS website they would normally supply the skimmer with a mag7. So the comparable rio would be a 1700. The problem I am having the skimmer takes forever to create any gunk. I also saw on there site it can take up to two weeks to "adjust" is that crazy? In my 55 gal oceanic with a "oceanic" skimmer is starts up right away. It is a oceanic model 75 plus. The skimmer has a seperate pump with a air pump. Is this just the nature of the beast with this style skimmer. If I even add water to my sump for evap top off it sends the skimmer all whacky and takes a couple of days to readjust. And lately here in Chicago I have been adding water every day. Can anyone give some ideas.