Seachem Acid BufferSeachem Acid Buffer is a non phosphate buffer to lower pH and 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. Lowers aquarium pH and buffers from 6. 0 to 8. 0 Converts alkalinity into CO2 For the planted aquarium or very hard water Seachem Acid Buffer lowers pH and buffers between 5. 0 and 8. 0 when used with Alkaline Buffer. As Acid