API pH Up API pH UP raises pH to make aquarium water more alkaline. It is designed to raised the pH of aquarium water where testing has shown pH to be at an undesirable level. pH is the measure of acidic or alkaline conditions of water. A value of 7.0 corresponds to a neutral pH. pH values about 7.0 are considered alkaline, and pH values below 7.0 are considered acidic. Different fish need different pH levels to be healthy. Check the pH level using a pH Test Kit. Benefits: Raises aquarium pH Features Fast-acting, colourless, easy-to-use and will not cloud or colour aquarium water Phosphate-free and nitrate-free, will not encourage algae growth.