Brown algae - suggestions needed

Hi. I am new to the game. I have a 29gal Oceanic BC about 2 months old. I have a media tray in place of bioballs in chamber 2 with chemipure and purigen. In chamber 1 I have Aquatic Life 115 skimmer.



Along with my live rock I have:

-Kenya Tree Frag

-Green Star Polyp Frag

-2 Clown fish

-1 Yellow Watchman Goby

-1 Royal Gramma



I also have Crushed Coral as the substraite.



Within the last couple of days I have been noticing brown algae accumulations in different areas on the CC and parts of the live rock. Also my Green star polyp closed up for a day. I read that brushing it softly with a toothbrush that it would. I did this and it did open up a little bit not as much as it was a couple days prior.



Does anyone have any suggestions on how to get rid of this brown algae problem. I did recently order a syphon kit, which should come in today to help clean the CC.



One last thing. I am feeding my fish the cubes of frozen shrimp. I feel like the pieces that I cut off the cube only have some chunks of shrimp and the rest just kind of disintegrates into the water and the fish dont even like it that much. Could this excess food be causing the problem.



Please help