There are tons of threads started on reefcentral about carbon dosing and some specific to sugar dosing. I don't have experience with sugar dosing, but have read alot and most people preffer either vodka/vinegar/biopellets. I dose vinegar and vitamin C together and happy with the result. different carbon source feeds different strains of bacteria, so some people like to use different sources of carbon for diversity. You should google more about them.