I have been dealing with GHA for almost a year now (after restarting my tank from full loss during hurricane Sandy), I have tried manual removal, Tech M, GFO, etc. The tech M dosing was the most helpful, but more so in ease of removal. I pull and siphon with weekly water changes and it just keeps growing back by the next WC. I just noticed some red brush popping up on a zoa frag as well... yay.
After browsing through this entire thread, I am excited to try something that is proven effective. I am not sure if spot or submersion would be best for me, I have four big rocks in a 34g cube, two of them are basically covered in HA.
If I go submersion, I have a few concerns, I have some emerald crabs that hide in the rocks and a chiton that is basically part of the rock when he settles on a spot. Will they be affected by the peroxide? With submersion, should I then soak in some tank water for an extended period to help with the dilution of peroxide before putting the rock (very porous pukani) back in the tank or will a dip in tank water suffice?
In any case, I will absolutely take before and after pics.