The 300 gram container of Seachem Acid Buffer is a non-phosphate buffer designed to carefully and quickly lower pH and buffer. It is created specifically for use in planted aquariums or for systems with very hard water where phosphate buffers may pose an algae or cloudiness problem. Acid Buffer lowers pH and buffers between 5.0 and 8.0. As the formula lowers pH it converts carbonate alkalinity (KH) into available CO2 to the benefit of your plants. It may also be used to safely lower pH in marine water.