Hey you are close to fixing it, just the willingness to access your rocks for hand guiding is all we needed
Most will not do that. You are missing the algae kill step portion of the removal, scrubbing is like lawn mowing where anchors are left to regrow. Do one test rock from this thread, then compare regrowth to your other attempts I bet this new added step works:
https://www.reef2reef.com/threads/reef2reef-pest-algae-challenge-thread-hydrogen-peroxide.187042/
Sub linked in that thread is over 500 gha fixes, it's rather easy for most accessible systems
Want to know what I feel one of the chief takeaways coming from the nine years of logged work above- algae doesn't usually signify anything wrong with the tank or tank params.
We've been trained by hobby posts: seeing coralline on a reef/ normal
See algae on a reef, something is bad go buy some testers and begin a months long half attempt.
Algae just grows because it gets all it needs from any reef where a beak or jaw isn't there to break it off the reef as food. We just chemically burn it off there during your normal access routine
Killing the holdfasts is why our test rocks keep beating other compared methods even though we haven't ever used a nitrate or phosphate test kit to earn the fixed tanks.
If you will separate the actions that prevent algae from growing away from the actions that kill it directly, you’ll win. Clean up crews, water adjustments, meds and dosers you add to the water, aren’t meant to remove algae that is in place due to natural adaptation. Cucs feed on algae in balance for a natural reef, they don’t rid the reef of algae they balance it. You are dealing with an invader that can take over your rocks, it shows, there is no room for balance just take all the ground now. Clean up crews do not fix algae invasions on real reefs, the algae just kills the coral where it finds adaptation. check the Netflix movie about corals it’s amazing as an algae study and causative video.
Apply new animals, clean up crews, water param balances etc in the clean condition not the invaded one. Cause the uninvaded condition, don’t wait or hope for it. When your tank is algae free then apply all the supports to keep it that way. doing the opposite is literally why gha problems rack this hobby for thirty years and hardly anyone is making ground. The algae posts just keep coming even though params are ok for most of the posters before the invasion, because in the ocean algae grows in all water conditions