The pH of an aquarium is a very important, yet commonly overlooked aquarium water parameter. A correct, stable pH will help ensure a healthy aquarium environment. The pH of an aquarium can fluctuate due to biological or chemical activity within the aquarium. With pH Decreaser, the pH may be decreased to a desired level for aquarium inhabitants. Adjusting the pH to the proper level has an important influence on fish health and disease resistance. pH adjuster for fresh and saltwater Increases acidity Reduces alkalinity Correct pH improves biological filter efficiency Directions & Dosage To decrease pH, add 5 ml (1 cap/1 tsp) per 20 gallons of water. Check the pH of your aquarium water prior to dosing. Depending on the initial acidity of your water, several doses may be required to reach the target pH. Wait approximately 10 minutes, re-check the pH level before adding more Fritz pH Lower. If fish are present, limit pH change to 0.2 per day.