Acid Buffer is a non-phosphate buffer to lower p H & buffer with Alkaline Buffer. Both buffers are designed for the planted aquarium or for very hard water where phosphate buffers may pose an algae or cloudiness problem. Acid Buffer lowers p H & buffers between 5.0 & 8.0 when used with Alkaline Buffer. As Acid Buffer lowers p H it converts carbonate alkalinity (KH) into available CO2. It may also be used to safely lower p H in marine water.