Cleaning older rock

[Myka]

Bleach is actually quite reef-friendly because it doesn't leave behind any residue and off-gases all on its own. As long as what ever you're cleaning fully dries (such as filter socks) it will be chlorine free. Or in your case, it will off-gases eventually if still wet.

When I was culturing fish, I'd sterilize the larvae tanks including the water with bleach before hatching the eggs. The water was bleached with 1 mL per gallon and then dehlorinated with Sodium thiosulphate. The eggs would get a peroxide dip too so they were born into quite a sterile environment. Ammonia was dealt with by detoxifiers.