Who was it that used this for cynobacteria or blue/green algae? Ron? dattack? Well my filter got clogged with some java moss I was trying to prune, and I had very slow water movement towards the bottom of my 29 gallon. As a result, I noticed a few pieces of gravel getting some. Well I cleaned the filter, and vacced the gravel. More water changes, cut the lights. Anyways, it is getting worse, and I wondered who used the maracyn for it and if you could let me know exactly how long you used it for and ect. There is also maracyn 2 out, so which did you use. If anyone else has a way , let me know. BTW, melafix did NOT have any effect on it.That stuff smells like it has Vicks in it.