Most likely the Cyanobacteria's source is due to overfeeding and uneaten food accumilating. It has been a year and you might have to add some replacements to the clean up crew. Some do perish and they need replenishing. I have had this problem in the past as well. Just do a 20% water change, add some phosphate remover (phosban, phosguard, or phosphate removing sheets), decrease feeding. I use 1/2 cube each between my 55 gallon and my 90 gallon. It is more than enough. It will be a constant battle if you don't treat the source. I also have a serpent starfish that gets all the stuff in the nooks and crannies that others can't get to. Add a few more blue legs, a few astrea, and a few other varieties of snails like nassarius are great additions. Also add some more flow so things do not settle in certain areas that are dead spots. Good luck we all have delt with this. I have more than I would like to admit. When every thing else fails I use chemiclean red slime remover. It works great and my inhabitants have not ill effects.