Total alkalinity is one of the most important tests in maintaining a healthy pond. As the beneficial bacteria do their job of breaking down fish waste and converting it through the nitrogen cycle they produce acids, thus lowering your KH. We shoot for a KH of 100-120 ppm. The KH acts as a buffer to the pH. When KH drops below optimal levels your pH begins to swing, causing beneficial bacteria to become weak or even begin to die off. Once you lose that good bacteria, the fish waste is no longer processed and will cause ammonia and nitrite to rise, both of which are toxic to your fish. Heavy rains will also contribute to lowering KH due to the acidity. Fortunately KH can easily be maintained by testing and using sodium bicarbonate / baking soda to raise it.
Taylor Total Alkalinity (TA) test
1) Place 25 ml of pond/tank water into a clean glass container.
2) Take the R-0008 (blue) bottle and turn it upside down & perpendicular over the container of test water. Add 5 drops of the blue total alkalinity indicator (R-0008) into the test water. The test water will turn blue/green.
3) Take the R-0009 (Sulfuric acid) bottle and turn it upside down and perpendicular over the test water. Count each drop of the Sulfuric acid (R-0009) as you add it to the test water. When the color of the test water turns from blue/green to red, multiply the number of drops added by 10. The resulting number will be the number of Parts Per Million (PPM) of TA in this test water.
4) Try this test on your source (tap or well) water for starters.
5) The acceptable level of TA should be maintained above 100 PPM. This can be accomplished by adding baking soda (BS) (sodium bicarbonate) For example: if the TA is between 50 & 100 PPM you should add ½ a cup of BS per 1000 Gal of pond/tank water.
6) Testing should be conducted at least weekly & TA adjusted accordingly.