If your tank is less than 6 months running, you can expect to see several different sorts of outbreaks.
How old is your tank? What are your water parameters? What kind of water are you using? (Treated tap or RO?)
If you have good light (on a limited schedule) and good water flow, water parameters in good range, and are doing your water changes weekly...it will most likely run it's course & not be anything to get real excited about.
I think I've had all the outbreaks (& I did a semi-panic with each, LOL!) but they seem to be clearing up at 3+ months and a few needed changes (increased water flow & light cycle reduction). Also make sure you are not letting direct sunlight from a window or patio door hit your tank daily. Hope some of this helps....HANG IN THERE & keep asking questions when you feel the need