Alkalinity - KH Calculator
Amount of Baking Soda
Gallons ppm KH change DH change Pounds Ounces Grams

Alkalinity in the fish pond It is generally recommended that alkalinity be maintained between 80-200, although up to 400ppm is used by some ponders. People using bead filters favor higher alkalinity. Below 80, there is a chance of PH crash and the lower values should only be used by experienced ponders. While baking soda is an excellent buffer, long term use can be a bit of a pain. It is recommended that KH be adjusted by a maximum of 20ppm at a time.
Most test kits measure alkalinity in degrees DH, one drop = 1 DH = 17.86 ppm. So if you measure 9 drops, you could just put that in the DH field and it will show you the equivalent ppm.
Using the calculator Two of the three fields "Gallons", ppm KH Change or "Amount of baking soda" are required to calculate the third field. The calculator remembers the last field entered and will calculate the missing field, e.g., if you enter Gallons and then go to Amount, the ppm KH will be calculated or if you enter Gallons and then ppm KH, the Amount will be calculated.
Examples:How much baking soda?
A 2000 gallon pond needs to have the KH raised from 60 to 100ppm. Enter 2000 in the Gallons and then enter 40 in ppm KH. The amount of baking soda required will appear as pounds, ounces and grams. The number of drops on a DH test kit is shown in the DH field. Ideally, this would be added as two seperate doses of 20ppm each.
NotesThis calculator uses JavaScript.
I'm confident this calculator is accurate, but things happen. Use it at your own risk,
Calculators Provided by Koi and Water Garden Society of Central New York