Back story. Cyano infestation 2 months ago. Removed carbon filter and used chemi-clean with 50% water change. That fixed the issue and it ran fine since then until a week ago I realized I forgot to put the carbon filter back into the media basket. So I did and now started having cyano/algae problem again. So I'm just trying to understand what the carbon filter has anything to do with it. Can anyone shed some light?