You need to stage a multi front attack: assess your filtration, feedings, lighting photoperiod, bioload & h2o changes. these all contribute. Next keep a healthy population of detrivores to keep wastes from piling up & fowling the tank water. Consider adding an urchin, in my experience one of the best algae destroyers out there. Add a quality <phosphate resin to your sump. I have been algae-free for three years using this approach & I was plagued by hair & Bryopsis. Scrubbing the rocks will just spread algae like wildfire, pluck it off & try what I've mentioned. I also have a large UV on my set-up, like'em or hate'em, my tank is loads better since I added one.
