Water Garden Oasis Seachem Pond Acid Buffer - Lower pH in Decorative Ponds, 4 L/ 1 fl. gallon (2819) FeaturesCONCRETE PONDS: It is particularly useful in lowering the pH in concrete ponds. CHECK pH AFTER EACH DOSE! NEVER USE IN A NON-CONCRETE POND WITHOUT ALSO USING POND PH BUFFER OR A PH/KH TEST KIT.DIRECTIONS: Add 500 mL (2 cups) of Pond Acid Buffer to each 1000 L (250 US gallons) of pond water each day until target pH is reached.USE: Seachem’s Pond Acid Buffer is ideal for use with planted ponds containing koi, goldfish, or other pond fish.WILL NOT PROMOTE ALGAE GROWTH: Pond Acid Buffer is not eutrophic and will not promote algae growth.LOWER PH: Pond Acid Buffer is designed to lower pH in decorative ponds without the use of phosphate or phosphoric acid. .