Heres the deal. I have had an fo running for one year. Levels stay okay, ammonia between 0 and .25. I run a ugf only. I have a brown algae problem like you would not believe. I have pulled every rock at one time and scrubed them and then changed 20g of water. you name it i have tried it. Did i nopt cycle my tank right, or something. I want this crap to go away. I have no problem keeping fish, well except butterfly fish.