Aquarium water can fluctuate up or down due to biological and/or chemical activity within the aquarium. Using Kordon pH Increase to bring the pH up to a desired level, or Kordon pH Decrease to lower pH helps aquarists manage their aquarium's pH levels quickly and accurately. For best results it is recommended that Kordon pH 7.0 Freshwater: For Goldfish, Koi and Community Fish, pH 7.5 Brackish water: For Scats, Puffers, Monos, Mollies and Cichlids or pH 8.2 Saltwater: For all Saltwater Fish and African Rift Lake Cichlids Stabilizer products be used following treatment with either pH Increase or pH Decrease for complete pH water control. PH Stabilizer products sold separately. Each bottle treats 2,800 gallons.