pH Up is a liquid pH raising product for freshwater aquariums. By neutralizing acidic substances in the aquarium, pH Up effectively makes the water more alkaline. The pH may rebound down to the original pH depending on the acid level in the aquarium. Several consecutive treatments with pH Up may be necessary to adjust pH to the desired level, but if there are fish present in the aquarium, the pH should not be changed more than 0.2 in a 24 hour period. While many common aquarium fish will live in water with a pH of 6.8 to 7.5, a pH of 7.0 is ideal for a community aquarium containing a variety of freshwater fish. Adjusting pH to the proper level will improve fish health, disease resistance, coloration, and breeding.