Acid Buffer, 4 kg / 8.8 lbs Lowers pH and converts alkalinity (KH) into CO2 A non-phosphate buffer to lower pH and buffer with Alkaline Buffer Designed for the planted aquaria or for very hard water where phosphate buffers may pose an algae or cloudiness problem As Acid Buffer lowers pH it converts carbonate alkalinity (KH) to available carbon dioxide 300 grams treats 3000 US gallons