API 4oz pH Up BottleAPI pH UP pH adjuster raises pH levels in your aquarium to make water more alkaline when levels fall too low. pH is the measure of acidic or alkaline conditions in water. Key Features: Contains one (1) API pH UP Freshwater Aquarium Water pH Raising Solution 118 ml Bottle Raises freshwater aquarium water pH with a phosphate free formula Does not promote algae growth with pH adjustments and is safe for plants and fish Slowly neutralizes acidic