You will definitely want to consider getting some snails and maybe some crabs in there as part of a Clean Up Crew (CUC) to help clean your tank. I'm not sure what size tank you have, but you'll want to gradually build up a CUC that will work well within your tank and to your liking as well. I'm particularly fond of Mexican Turbo Snails for GHA, Nassarius Snails for detritus (fish poo and left over food), Nerite Snails, and Cerith Snails. I also like Emerald Crabs as they tend to leave others alone unless they get in their territory. Some people like Hermit Crabs, but you'll need extra shells for them to move into or they will attack the snails you might get for their shells. I myself have a Long Spined Sea Urchin that is mowing down GHA for me, as well as a couple of Yellow Lettuce Sea Slugs.
Do some research to see what you like for yourself, as there are many options. Don't add too many at once, as they carry a bio-load to your system as well.
I'm not sure if you want to go about taking the rocks out and cleaning them with any chemicals, I'll leave a response to that for those you know best. But you can always carefully take them out, scrub them with a toothbrush or something similar, and rinse them in RODI water before putting them back in. I personally don't prefer doing this as there are other beneficial organisms on LR that I wouldn't want to scrub away, but many people do this with success and prefer no GHA over keeping other small organisms.