STN and GAC

[James404]

Been struggling lately with some of my SPS and just can't figure out what the problem is. Unfortunately a few things happened that could be the cause, so been trying to narrow it down. One of these changes was I started running BRS ROX carbon. I started off with the recommended dose of 1 tbsp per 10 gallons. I have read a few reports here and there of people having STN running it, anyone else have issues?

 

[Alex T.]

I had STN with ROX about a year ago. I don't know if it was directly related to the ROX or a change in salt. I switched back to my old salt but continued the ROX and by summer I had almost 80% losses of SPS. I know from reading some of Boomer's threads in the Chemistry forum that GAC, specifically ROX was more efficient at removing DOC from the water column than protein skimming. Protein skimming is reported to remove around 30% so that's a pretty big claim in favor of carbon.

I switched to the Lignite carbon from BRS and everything has been fine ever since. Maybe you should take the ROX offline from a reactor and run it more passively in the sump.

 

[James404]

Thanks, I have taken the reactor offline for the time being. Hopefully things will start to get better, some STN has been at the base, some at the tips. I know alk is the usual suspect but pretty positive its not the problem.

 

[sahin]

From my reading around of GAC and Rox in particular; too much in one go can cause STN. I think there may be a thread about overuse of Rox causing STN. Rox is one of the most effective carbon available and will really strip the water too fast for some corals adjust in a healthy manner.

 

[Reef Bass]

I went from running no carbon to running BRS rox in my 150g water system with lots of sps. I made the adjustment slowly, meaning the first "dose" (reactor chamber contents) was 1/4 cup. Then in a couple weeks, changed that out with a fresh 1/2 cup. Next change was to 1 cup which is what I usually run. I've run as much as two cups without issue, but I had been running carbon for a couple months at that point, so it was a gradual adjustment.