IMO, ceriths are ok. What about the flow in the area? Bet it is on the lower end in your tank. How old are the bulbs? How is the water testing, specificly the Nitrate and phosphate? Even at a year, the tank is still young. I shy away from putting chemicals in my tank that are either erythromycin (an antibacterial, how ironic, right?), or undisclosed chemicals that the company will not tell you anything about. Wait it out. Increase the flow, add some Ceriths...