I’d recommend pulling as much of the algae out as You can manually from your display but don’t go taking the rocks out and spraying them or dipping them in fresh water. Maybe rinse them in a bucket of salt water and scrub them a bit with a brush to remove as much detritus as you can but that’s it. If you go spraying them with peroxide and dipping them in fresh water your going to cause die off of the bacterial and organisms that live on the rock which will only amplify your problem. Like I said your real cure is to plumb in a tank of some sort and pound the light to it to get the algae growing there. It won’t take long to clean the tank up if you do it
