Can anyone tell what is this greenish spots of algae over my sand? The spots look like forming a start shape, is not covering the whole sand, but is everywhere only separate with fews inches in betwwen them. This is a new se up, I decided to start all over again after having a lot of problems with all kinds of algae. I let my tank cycle for 3 months. Water parameters are good except that I always get a litle bit of phosphate reading. This is a 75 gallon tank, with about 60 or 70 pounds of live rock, an in sump skimmer, but I also added a hang on the back skimmer ( Remora skimmer ) to better clean the water. During my cycling I kept the lights off, to avoid algae outbreaks. Now the tank has had the lights on for 2 weeks, everything is fine except I am getting these spots of greenish algae on the sand, what do you think are these, friends? I have 3 fishes in the tank, a blue tang a maroon clownfish and a sail fish.I have like ten snails that are doing a good job, but they are not eating these algae on the sand. Any body would know what I am having? your help will be very appreciated.