Nutrafin KH Booster, KH Increaer, 500 mL, helps stabilize pH levels with a plant friendly potassium based buffer. Recommended for planted aquariums as well as African cichlid and other hardwater preferring species of fish. It is strongly recommended to use KH and pH test kits when using this product, careful application is recommended in softwater aquatic enviroments as pH increase is expected in this instance.