I have 4 tangs, foxface, 6line, pair of perc's and i feed 4 cubes every other day. SPS dominated tank. I don't do water changs more than once a year. I use the 160 cone with the modified impeller and extra large collection cup. Nitrates and phos are undetectable. Corals grow like weeds. I used the 180 cone but don't sell them anymore because ive just had to many sicce psk issue's. I also used the 230 cone on my system for 4mths. It worked well but my tank is just to small. The 160 cone is more matched to my tank and outskimmed the 230 cone because of that reason. Now if i were to throw the 230 cone on a 225g tank and the 160 cone on a 225g tank the 230 would skim circles around the 160. Its just the fact there isn't enough waste to keep the 230 cone satisfied. When i run a skimmer i want to see consistent skimmate every week. With the 160 cone mod i see this, with the 230 i did not. On a bigger tank you would see consistency with the 230 cone.
PS- There isn't a better pump out there than the laguna based motorblock. The laguna model is the max flo 1500. The atman isn't in the same class as the askol, but its quiet, cheap and works well.