Tank looks pretty new.
Some ideas.
-If not already, get some mechanical filtration running, put on socks, an hob, etc.
-increase aquarium flow, you want the next part to stay suspended as long as possible.
-scrub the rocks with a brush inside the tank.
-next check you po4 and no3, tanks with low living export members, excess nutrients are going to lead to algae. I like the red sea kits on both wont break the bank and accurate enough.
-adjust your feeding, based on your readings.
-add more corals, pods, macro algae, snails, anything that will complete with or eat the algae.
*if nutrients are way out of wack, a few water changes during scrubbing will also help. I would not jump to carbon dosing or gfo right away as can lead to issues as new tanks often have fits of abundance and lulls with micro and macro inhabitants, that can cause nutrients to rise and fall. Unless constantly testing to ensure stay above 0.