what’s cooking?

I recently got some rock from a local reefer, about a hundred pounds in all. While the rock isn’t the best, there’s some heavy boulders in the pile, it will still certainly help increase the amount of live rock that I have in the system. I’ll probably store most of it in my sump, or swap out some of the uglier pieces of live rock in my main system.

I know the rock has been in a few other systems and since I’ve recently gone through a red cotton algae breakout recently, I’ve become wary about what I’m putting in my tank. Cooking the rock is a process of putting the rock, submerged, into a dark place with a heater and powerhead and leaving it for a few months. The idea is to kill off any algae and other pests like aiptasia by starving them from light.

Of course, it’s a bit more complicated than that. Water changes are important for nutrient export. I’ve been doing a 50% water change every week or so. Emphasis on the ‘or so’. The first couple of weeks were a real treat. Nearly everything died off and rotted. There was a rotting smell in my basement and a brown thin layer of protein on the water surface.

I’ve had the rock in a 20 gallon brute garbage pail since April 9th. Today, I cleaned out the rock, washed everything down and got as much of the gunk out of the bucket as I could. Here’s the process I took, it’s the same process I took to make the rock in the first place, so if you’re just starting out, you can follow along.

This is the setup. You can see the live rock vat in the background. I had three buckets of water from my tank. The buckets were to swish the rock around to clean it. Later on, you’ll see why there were three buckets. Make sure you have lots of help. Mine’s in the foreground helping me with the heavy lid.

You can see that there’s still some algae growing on the rock even after three weeks in darkness. I was surprised that I didn’t come across a lot of pods or other microfauna. I would have expected a population explosion with all the detritus. There were even a few stray zoas still alive. The rock towards the bottom of the pail was pretty stinky. I don’t think I had enough circulation down there.

Below is the reason I had three pails of water. I started with the bucket on the left, swished the rock, moved to the next pail, swished, next, swish, place in the now clean garbage pail. Repeat. I did this when I first put the rock in the pail and I was amazed at how dirty my rinse water became. I’m still amazed that the water is this dirty. I’ll probably do this process one or two more times before I’m done.

Finished! Here’s the rock back in the pail. The rock barely fits in the pail and the top of some rock is exposed but I don’t think that will be a big deal. The pipe runs to the bottom of the rock, so the water is moved evenly. On the right is a small heater.

And that’s all there is to it! The rest of the process is patience. I’ll probably do another change in a week or so, and maybe completely rinse all the rock in three or four weeks.