Seachem Acid Buffer 300g
Lowers KH to lower PH in stubbornly high PH water.
Uses: Acid Buffer™ is used in conjunction with Neutral Regulator™ when the PH is very high or is difficult to lower to 7.0 with Neutral Regulator™. It reduced the carbonate hardness (KH) of the water, making the PH much easier for other products to buffer. If your PH is very high and reisstant to buffering, Acid Buffer™ is your answer.
From the manufacturer: 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. Acid Buffer™ lowers pH and buffers between 5.0 and 8.0 when used withAlkaline Buffer™. As Acid Buffer™ lowers pH it converts carbonate alkalinity (KH) into available CO2. It may also be used to safely lower pH in marine water.
Directions from the manufacturer: To lower pH, use 1/4 teaspoon (2g) for every 80 L (20 gallons) daily until desired pH is reached (this dose lowers alkalinity by about 0.2 meq/L (0.6 dKH)). Larger doses may be required in very hard (KH) or alkaline waters.