Seachem 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. A 300 g bottle treats over 900 gallons.