| Testing the quality of the water in your pool is the | | | | common and cheap. OTO (OrthoTOlidene) reacts |
| most important step to ensure your pool is safe, | | | | with chlorine and changes color. OTO kits also |
| clean and refreshing. Proper water balance will also | | | | measure pH which is why they are often called Duo |
| extend the life of your pump, filter and any other | | | | test kits. Unfortunately, OTO kits are pretty useless |
| equipment as well as making pool care quick and | | | | for measuring all-important free chlorine. The reaction |
| easy. | | | | that produces the color change is a two-stage |
| So, just what should be tested and why? First and | | | | reaction; the first change measures free chlorine and |
| most importantly, the sanitizer (chlorine, bromine etc.) | | | | the second combined or total chlorine. The free |
| needs to be within the proper range. Next pH and | | | | chlorine reaction happens SOOOO fast that it's |
| total alkalinity need to be monitored. When testing | | | | virtually undetectable. In practice, an OTO kit is only |
| sanitizer the only useful measurement is for free | | | | reliable to measure pH! |
| chlorine or bromine; free means available for duty. | | | | DPD kits actually measure free chlorine as well as pH |
| Sanitizers are used up in keeping water clean as it | | | | and alkalinity. They are a proven technology and |
| combines with contaminants and forms chloramines. | | | | recognized by most Health Departments as the |
| Chloramines are irritating, useless and need to be | | | | acceptable way to test public pool water. There are |
| removed but form a component of Total Chlorine. | | | | drawbacks. Accuracy of test results is influenced by |
| All water has pH that is a measurement of acidity or | | | | the freshness of the reagents, particularly DPD and |
| alkalinity. If pH is too low water will tend to be | | | | the experience of the tester. DPD testing is also |
| corrosive, especially to any metal like heaters or | | | | somewhat time consuming and complex but properly |
| ladders. If pH is too high the water will tend to form | | | | done the test is quite accurate. |
| scale inside the pool. To maintain the proper pH level | | | | Test strips are newer and truly a better way to go. |
| of 7.2 to 7.8 Total Alkalinity needs to correct. Total | | | | Extremely fast and easy a strip is stuck in the water, |
| Alkalinity measures dissolved carbonates in the water. | | | | removed and the reactive color changes compared |
| These carbonates help buffer or "lock" pH at its | | | | to a chart right on the bottle. The basic three-way |
| proper level. | | | | test strip measures free sanitizer, pH and total |
| So testing for sanitizer, pH and Total Alkalinity is vital: | | | | alkalinity at a glance. The results are not quite as |
| what's the best way to do it? | | | | specific as a DPD test but will definitely indicate |
| Glad you asked! There are three types of pool test | | | | whether the water is in the proper range or needs |
| kits commonly sold: OTO kits, DPD kits and Test | | | | attention. The test is so easy that regular use is no |
| Strips. The first two kits, OTO and DPD, are named | | | | pain at all. Test strips are now on the market will test |
| for the reagent that tests the sanitizer level. These | | | | everything from Baquacil to nitrate and salt levels. |
| are the kits commonly portrayed with test tubes and | | | | The choice of test kit is, of course, up to each pool |
| eyedroppers. Adding reagents to the test water | | | | owner but if you want the right information throw |
| produces a color change that is compared to a chart | | | | out that Duo Test kit and switch to test strips or a |
| and gives a value for the component being tested. | | | | DPD kit. You'll spend less and enjoy the pool more |
| Test strips also use color comparison but are dipped | | | | 'cause you know the score. |
| directly into the water. | | | | Rob "Dr. |
| OTO test kits have been around the longest and are | | | | |