Seachem Acid Buffer is a non-phosphate buffer for lowering pH in freshwater aquariums. It is designed for use in planted aquariums or for very hard water. Acid Buffer converts carbonate alkalinity (KH) into available CO2. Its phosphate-free composition prevents algae or cloudiness problems. When used alone, it reduces pH. When paired with Seachem Alkaline Buffer, it provides stable buffering for planted tanks or very hard water without adding phosphates.