Bob, are you using Red Slime Remover?
Personally, I believe the problem is that you are only treating the symptom, and not the cause. I don't think using a product to get rid of cyano is going to help in the long run. You need to figure out the underlying cause of the cyano, which is going to be a buildup of nutrients in the system. You need to review what is going into the tank vs. what is coming out. Start a series of water changes, vacuum the sand bed, use a powerhead or turkey baster to blast the detritus out of the rockwork, siphon off what cyano you can every few days and blast it off of the corals to keep it from smother the corals, etc. I typically throw a filter sock on, and use the turkey baster on the rockwork and blast the sand bed every few days if cyano starts to appear. It's growing for a reason, and that will always be an input vs. export issue. Good luck.