Anytime I have experienced Cyano out of control, I have re-evaulated my feeding practices and my light schedual. Have you tried cutting back in these areas as well as your bulb life, water parameters, etc.? Sounds like you've been checking everything, and sometimes the simplest answers are grest! You didn't mention your light schedual, but I tend to cut back to 6 hours or more for a few days. This helps the situation greatly. I try to remove any "sheets" of cyano with a spatula (good old fashioned egg flipper in plastic). This allows me to get a good amount out in one sitting without making it spread all over the tank. Cutting down your feeding will help as well if that is an issue. Without more information from you on how you actually feed, this is all I can suggest. I will do my best to follow up with you here, but if you don't get an immediate answer, please PM me for information. I'm sure others here will jump in to help as well! :D Good luck, and I will talk with you soon. ....Angel :angel1: