API PROPER pH 7.5 automatically sets and stabilizes pH at 7.5, and removes chlorine and detoxifies heavy metals. PROPER pH 7.5 also contains electrolytes to reduce fish stress and boost overall health. pH is the measure of acidic or alkaline conditions in water, where a value of 7.0 corresponds to a neutral pH, pH values above 7.0 are considered alkaline, and pH values below 7.0 are considered acidic. Different fish need different pH levels to be healthy, so it is important to test your water regularly to ensure pH levels fall where they should. If water does not test at the desired pH level, use API PROPER pH 7.5 to adjust and hold the level for fish such as Goldfish, Barbs, Central American Cichlids, and general live bearers like mollies, swordtails, and guppies. For use when setting up an aquarium, or when performing a water change.