Question about cycling rock
 

I have a large piece of rock (about 5 lbs) that is covered by some ugly zoas and gsp. I am planning to take it out and let it go dry to get rid of the zoas and gsp. Once the rock has gone dry, would it be okay to put it back into the tank or do I need to cycle it? If it does need to be cycled, how long would that be?

All the die off inside the rock will leach phosphates into the tank, probably giving you some algae issues.

Brad,
I have about 150 lbs of rock in the tank, would a 5 lbs piece be releasing significant phosphate that would be a problem??

If your up for a trade ill trade ya. dry rock.

I don't know either way, but i wouldn't want to find out. If it was a piece of rock that I just couldn't throw in the garden, I'd probably boil the crap out of it then soak it in RO for a while.

Soak it in vinegar for an hour with no circulation. The vinegar will kill of the outside layer of the rock, but with no circulation very little vinegar will make it into the rock. After the vinegar bath put it in a bin to cycle and check that nothing grows back. You might have to do the vinegar bath a couple times. If it was summertime I would suggest using a powerwasher on the rock to blast the corals off before the vinegar bath.

I've done this several times with no problems. I just rinsed and scrubbed all the dried up crap off the rocks and put them into the sump. Probably the safer bet would be to do the vinegar thing though.

:thumb:
I have done this too many times.

The safest way is simply to a trade with someone else's base rock or a trade with a dry rock weight for weight.

If It were me, I'd try this...

Vinegar soak, scrub off the unwanted corals, rinse, place in toilet (clean water side) to leach out the rest of the die-off, RO rinse, then into the sump for a cycle.

I'd also avoid any boiling as you never know what toxins are in your zoa/paly's.