2 koralia 1's is 800 gph. that should turn over the volume of the tank 27 times an hour (over 30 times if you count canister, which DOES put out a good current). Anyway, I had a hard enough time finding a combination of diretions to point the powerheads and didn't make my feather duster and sofities hide all the time from being battered by the strong current. it's a 30 long, maybe that makes a difference.

And since I'm on the slow (low budget) salt water hobbie track, it will be several months before I can buy the lighting upgrade I want. Maybe sometime after that I can consider another upgrade on skimmer, though I thought mine was good as far as HOT goes. And Sump would be too much trouble for now. That or save up for RODI, or any other number of nice-to-haves.