I have stopped using this stuff since my last post. I am using good husbandry (water changes, lots of water flow, blow off LR) to keep phosphates and nitrates at minimum levels. I'm sure the over-sized skimmer isn't hurting anything either. Now, there is one less piece of equipment to maintain, one less item to purchase regularly. As I get more and more into reef keeping, I can't help but notice the plethora of items to fix things that can be remedied in the first place. My using GFO was a crutch so that I could be lazier than I should have been.