API® pH DOWN pH adjuster lowers pH to make freshwater aquariums more acidic for fish and plants when levels rise too high. pH is the measure of acidic or alkaline conditions in water, where 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, so it is important to test your water regularly to ensure pH levels fall where they should. pH DOWN pH adjuster is fast-acting, colorless, easy to use, and will not cloud aquarium water. Because it is phosphate-free and nitrate-free, pH DOWN pH adjuster will not encourage algae growth.

Determine the pH of aquarium water with an API pH TEST KIT. To lower pH, add 1 ml. for each 10 gallons of aquarium water.

Take another pH reading before adding another dose of pH DOWN pH adjuster.

Some fish may be sensitive to pH adjustments greater than 0.2 in a 24 hour period, so changes of this magnitude should be done with extreme care.