Seachem Acid Buffer is a non-phosphate buffer used to lower pH levels in Freshwater Aquariums, opposed to Seachem Alkaline Buffer which raises pH. Both buffers are designed for the planted aquarium or for very hard water where phosphate buffers may pose an algae or cloudiness problem. Seachem Acid Buffer lowers pH and buffers between 6.0 and 8.0 when used with Seachem Alkaline Buffer. As Seachem Acid Buffer lowers pH, it converts carbonate alkalinity (KH) into available CO2.