Hanna Instruments 

HI7754 Pool Line Checker® Handheld Colorimeter is designed for the measurement of alkalinity in swimming pools, hot tubs, and spas. Alkalinity is a very important parameter in monitoring swimming pool water chemistry. Alkalinity is the buffering capacity of a solution to resist a pH change from the addition of an acid or base. This can be a challenge when using common forms of chlorine, in that, as a base when the chlorine is added the pH will increase. As the pH of the water increased above pH 7.4 the chlorine becomes predominately in the hypochlorite form instead of the hypochlorous acid as the pH decreases from pH 7.4. Hypochlorous acid is 100 times more effective as a sanitiser than the hypochlorite form. When water is low in alkalinity the pH will increase as the chlorine is added. When there is adequate alkalinity then as the chlorine is added the base is absorbed and the pH remains the same. Monitoring alkalinity is important in maintaining a stable pH of a swimming pool hot tub, or spa.

The contoured style of these Checkers fits in your palm and pocket perfectly and the large LCD is easy to read. The auto shut-off feature assures the battery life will not be drained if you forget to turn it off.

To perform a measurement of the instrument a water sample is placed into a cuvette and the meter is zeroed. Next, a reagent is added that will react with alkalinity to produce a distinctive range of colours from yellow to greenish-blue. Last, place the vial into the Checker, press the button and read the results. It’s that easy. It is important to note that if chlorine is in the water sample to be tested then it is necessary to add HI937554-53 chlorine remover first before proceeding with the test.