This bottle of reagent grade ammonium chloride is for use when fishless cycling.Concentration is 40 mg/ml of total ammonia-nitrogen (TAN).Dose 4 drops per gallon of aquarium water.* Use with One and Only Nitrifying Bacteria.

Generally during a fishless cycle you need to add ammonium chloride to your tank 3 times so:
a 2 ounce (60 ml) bottle will cycle 100 gallons (359 liters)