Reeflowers RemOrganics Fish Aquarium Water Conditioner, 2.9-fl oz bottle

It is recommend that 2/3 tsp (3 mL) of RemOrganics is added for every 26 US gallons (100 liters) of water on a weekly basis (for an average loaded aquarium).

In the case of an emergency such as water contamination, ammonia spikes, or long periods of power failure an additional daily amount of 2 tsp (10 mL) can be added per 26 US gallons (100 liters). Following dosing of medication, add 2/3 tsp (3 mL) daily over a period of one week. When transporting fish or invertebrates, add 1/4 tsp (1 mL) of RemOrganics per 2.6 US gallons (10 liters) of aquarium water.

85 ml bottle - 20 drops = ~1/4 tsp (1 ml) 250 ml & 500 ml bottles - 1 cap = ~1 tsp (6 ml)