<a href=showthread.php?s=&postid=13927557#post13927557 target=_blank>Originally posted</a> by reefkeeper2
This question keeps popping up. There are some excellent threads here on Reef Central about carbon dosing (vodka in this case) that can explain it in greater detail. In my case, I was feeding large amounts of food to keep non-photosynthetic corals. I used the vodka to help keep nutrient levels down. Essentially, your feeding bacteria in your tank a carbon source that promotes their growth. As they reproduce, they consume the excess nitrate and phosphate in you tank.