From the bottle;
Removes chlorine, chloramine, ammonia,
Detoxifies nitrite and nitrate,
Provides slime coat
Prime is the complete and concentrated conditioner for both fresh and salt water. Prime removes chlorine, chloramine and ammonia. Prime converts ammonia to a safe, non-toxic form that is readily removed by the tanks' biofilter. Prime may be used during cycling to alleviate ammonia/nitrite toxicity. Prime detoxifies nitrite and nitrate, allowing the biofilter to more effiiently remove them. Prime also promotes the production and regeneration of the natural slime coat. Prime is non-acidic and will not impact pH. Prime will not over-activate skimmers. Use at start-up and whenever adding or replacing water.
directions: Use 1 ml (top mark of enclosed dispenser) for each 40L (10 gallons US) of new water. for larger doses, note that 1 capful (5ml) will treat 200L (50 gallons US). (Note the 2 and 4 L container's cap is 10ml). this does removes approximately 0.6 mg/L ammonia, 3 mg/L chloramine, or 4 mg/L clorine. May be added to aquarium directly, but better if added to new water first. If addding directly to aquarium, base dose on aquarium volume. Sulfur odor is normal. For exceptionally high chloramine concentrations, a double dose may be used safely. To detoxify nitrite in an emergency, up to 5 times normal dose may be used. If temperature is >30C (86F) and chlorine or ammonia levels are low, use a half dose.
I must say, that's well written. It covers all normal situations and the abnormal situations.