Contains no phosphate Alkaline Buffer™ is a non–phosphate buffer to raise pH and alkalinity (KH) and buffer with Acid Buffer™. These buffers are designed for the planted aquarium or for very hard water where phosphate buffers may pose an algae or cloudiness problem. Alkaline Buffer™ raises pH and buffers between 7.2 and 8.5. It is gentle, safe, and enhances the freshwater environment.