I once had some old rock which was covered in hair algae. It sat in a bucket until the water evaporated and needless to say it was not suitable for my tank. I let it sit in a mixture of a 20:1 mixture of unscented Clorox bleach to RODI water for a week. After a week I soaked it in tap water with seachem prime for another week. After that I dried it out in the sun and then soaked it in RODI water for another week. (As you can tell I wasn’t in a hurry).
That’s my process. I probably could have gone for a shorter amount of time, but this rock was covered in a ton of organics.
It’s been a month now and everything is happy. Nothing has died—I have an acro garden and various other corals. Here’s some progress photos of the tank:
Before rock
Added bleached rock
Today
I’ll be doing another ICP test next month and we’ll see if it added any unwanted metals—I doubt it though. Most importantly, everything in my tank is happy, and my nutrients are close to 0.
Very nice tank
