For the past few months, I have had a slimey green algae (with patches of brown algae) infest my fish-only aquarium glass and rocks/dead coral. It's not the typical algae I used to get (leafy and easily wiped clean with a sponge). I tried scrubbing some of the rocks, pieces and the glass to remove the algae, but it almost seems permanently baked in. It looks very unpretty, and I know it's affecting my water clarity.
The water parameters are all norm, and my fish seem healthy. I haven't been using any chemicals and perform patial water changes every 2-3 weeks. My lighting consists of one Coralife 50/50 and one Coralife 10,000 degree K
bulb, and the tank is not in any direct sunlight. I operate the lighting from 9:30 AM to 9:00 PM each night (via timer).
Any ideas as to why this slime is growing or what I can do/use to prevent it is appreciated!