Using Nutrafin Aqua Plus Tap Water Conditioner is easy. When you're filling your aquarium with tap water, just add the conditioner according to the size of your tank. The product label has a guide on how much to use for different tank volumes. Before adding fish to the tank, make sure the conditioner has been well - mixed with the water. Keep in mind that this product is specifically for use in tropical fish aquariums. Don't use it in other types of water systems. Store the conditioner in a cool, dry place away from direct sunlight. Check the expiration date on the bottle and don't use it if it's expired. Regularly test the water in your aquarium to ensure the water quality remains optimal for your fish. If you notice any changes in your fish's behavior or health, consult a professional in the aquarium field.