Tetra Water Clarifier works fast to clear hazy cloudy water without affecting bio-filtration pH or other water chemistry. The phosphate-free formula does not contribute to algae growth and is safe for use in soft-water conditions in all freshwater aquariums. Quickly clears cloudy and hazy aquarium water Safely settles minute particles Phosphate-free formula Tetra Water Clarifier causes small particles to fall out of suspension allowing them to be removed by normal power filtration or gravel cleaning. . Directions: Add 1 teaspoon of clarifier for every 10 gallons of aquarium water. Freshwater systems will begin to clear in several hours. Repeat as needed allow 48 hours between doses. Important: Safe for fish in very soft-water conditions. However if in extremely low water conditions (below 1° kH) half doses are recommended. If in doubt about your waters condition do a 20% water change prior to treatment. Be sure to use a water conditioner for each partial water change and water test kits to measure your waters hardness.