pH-Ease decrease is a blended formula of several ingredients in deionized water. To insure the continued health and safety of the fish, the adjustment should be no more than 0.5 degree of pH change in a 24 hour period. As with all pH adjusting products, the alkalinity level (water hardness), should be adjusted to a normal range of 100-200 ppm (parts per million) before any effective and stable pH adjustment can be made.