schiavonir - It says full results in 72 hours, but I noticed it in 24. You have to change filter pads quite frequently during the treatment and let your skimmer run. The cyano is all gone, but there is a few piles of hair algae still there. My guess is they will use up the rest of the Phos with the macro and then everything should return to a nice balance. By the way - was safe on anemones, seahorses and macro. Definatley worth it IMO.