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Old 01/11/2008, 09:59 PM   #24
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Join Date: Jan 2007
Location: Athens, GA
Posts: 839
I just removed 25G of black funky water and I'm replacing it with just enough water to keep all the rocks immersed, about 12G. I'll do another big water change tomorrow. The good news is the black layer on the rocks is just a thin biofilm. After I ran some water over them from a pump it comes right off, they're nice and pretty underneath.

So, here's my thinking about what happened:

The dry rocks contained quite a bit of dead material, providing a source of nitrates, phosphates, carbon, etc. When I added the water, including some tank water from an established (and doing very well, lest you doubt my reefing abilities) tank, the added bacteria exploded. I first saw a "white" bloom, I'm assuming aerobic bacteria, which consumed all of the oxygen in a tank with no surface water movement. Then, the anaerobes exploded. I was expecting the white bloom, and was hoping that the biofilms covering everything would cause a lot of the rock dust blowing around to adhere to them. No luck there. The fact that the tank was over 83 degrees just made everything happen even faster.

My reasoning behind adding the sugar and ammonia: I wanted a mild bacterial bloom to begin breaking down all of the dead material, and I figured ready C and N sources would be an easy way of doing it. Well, it worked, just too well. I won't be adding any more
I didn't go with live rock mostly for cost reasons ($100 for dry versus ~$300 for live) but also to control pests.

My plan at the moment is finish this water change, do another one tomorrow, go to the LFS and look for a 1um filter of some sort, ask around the local club for a skimmer to borrow while shopping for one of my own, and really aerate the tank. After that we'll see what happens... I can't say I'm really that upset about this, it's an interesting problem.

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