What I did when I had GHA and bryopsis, I saved some old water from doing weekly waters changes. So once I had 10 to 15 gallons saved up, I pulled my infected rocks and scrubbed the hell out of them in the old water with a brush. Then scrubbed some more. Took a few tries for some of the rocks but man the sure beat what I was doing.
Might not be as easy for you as I have small rock in my BC29, I am sure some of your rocks are huge.
Might not be as easy for you as I have small rock in my BC29, I am sure some of your rocks are huge.