I have been wanting better growth from my zoas, and I have reduced my water changes to one a month and my zoas have never looked better, not much growth yet, but some, but they are looking good. I am about to try one more thing in my tank: As Guygettnby has said you can't compair one tank to another but, we have a small reefing community here where I live and have another reefer here that has a 180g mixed reef tank. This reefer has never had a skimmer in their tank, never, they use a filter sock in their tank and do a water change, every three or four months at best, and grows zoas colonys of I would say 100 polyps each, this reefer has started lately, with in the last three months, running a GFO and Carbon reactor . The fish load in this reefers tank I would say is most likely normal for a tank of this size, no really big fish in the tank but alot of small fish in the tank, my tank hasn't alot fish, just 6 in a 125g tank, but my Hippo Tang and my Foxface are big fish. Soooo, what I am going to try next is to turn my Reef Octopus skimmer off, say three days a week at the start and see what happens, put my filter socks back into the tank on the days I don't run the skimmer and change them out every day and see if I start getting better growth. I have to try something, I am not happy with the growth that I am getting at the present time.