I can't remember off the top of my head, but don't the instructions say 1 cap full per 10 gal. after a water change then 1 cap full per 40 gal. per day after that? I could be wrong. Be careful, too much Excel will have ill effects on your fish or shrimp! I have a 40 gal. heavily planted tank with rummys and pencil fish and I add 2 cap fulls every day along with a high tech CO2 system and the 2 cap fulls per day seem to be good!Just want to find out if 1 cap full per 10 gal which the bottle suggested would be enough carbon source for the my tanks. Been dosing everyday with this but is it too much?