Funny this topic should come up... I just asked about this last weekend while I was out at CAReef
I wanted to drop my nitrates below 5ppm to see if I could improve the color and growth of my SPS. And reading this article:
http://reefkeeping.com/joomla/index...ar-dosing-methodology-for-the-marine-aquarium carbon dosing seemed like the way to go (in addition to removing lots of fish, doing lots of water changes).
I've been dosing 10ml/per day of distilled white vinegar in a 60 gallon (in line with what the article suggests). So far the results have been been good... my nitrates are solidly below 5ppm, though not quite down below 2ppm... yet. I may try slightly increasing the dosage.
I also notice some other changes. My skimmate has increased, presumably because there's more nitrifying bacteria to remove floating around in the sump. My alkalinity dropped slightly... was holding at 10dKh... now hovers around 9.5dKh... may try slightly increasing the alk dosage.
The corals are looking great! Better than I've been able to get them in a long time. My montiporas were the first to respond, both with intensified color and a small amount of visible growth. My acros were slower to respond, but the colors have intensified (but not brightened - may need more light). I'm also seeing much more polyp extension that I have in the past (may have something to do with them having less nitrates in the tank to feed the zooxanthelle).
Anyways... overall, I'm a fan of carbon dosing so far. Though I've never heard or seen anything on the long term impact of carbon dosing (e.g. does it have other side effects? does it have long term permanent impacts on nitrates? etc...)
I may try adding Microbactr7 to see if that has a further impact. But I'll wait for another couple weeks to make sure my results are stable first.