I've cured live rock before using bleach (I actually did it one rock at a time in a running reef with SPS with no ill effects). Unfortunately in this current case I can't cure, as the tank came with fish and some brown coral and is too small to cope with uncured rock. It was more the scrubbing down of the rock which I may follow, as I've never really had hair algae before now. Anyway, i'll stop taking up your tank journal with my problems and start my own... .