POOL CARE KEY #5 - TESTING

Pool & spa water has chemical characteristics which must be measured regularly. You have has a responsibility to check two of these characteristics on a regular basis:

• pH
• Sanitizer

When these two factors are maintained within specified ranges, the water is less likely to experience problems. By testing these two factors on a regular basis, you will be able to understand how bather load, weather conditions and chemical applications affect the water. By understanding the water's personality you can anticipate potential problems by recognizing changes in these primary tests. You still must bring in a sample of water each month so that we may perform a more comprehensive set of tests. This insures that all the important parameters are in balance.

(Note from Pool Emporium, Inc.: We also feel it is critical that you test your Total Alkalinity on a weekly basis. We suggest pH and sanitizer levels be checked daily, or at least every other day. Additional tests should be done after heavy rainfall or bather load.)

By maintaining your pool water in the proper test ranges, it will be:

• Safe from uncontrolled bacteria growth
• Clear, sparkling, inviting
• Comfortable to the eyes or skin of swimmers
• Protecting the pool surfaces & equipment
• Free of opportunistic growth of algae

A WORD ABOUT OTO TESTS

OTO is another reagent used to test Free Available Chlorine, especially in home test kits. This is not an ideal reagent for use by a pool or spa owner. OTO has the potential of being easily misread because the color changes happen very quickly. The first, immediate color change that occurs in the sample will indicate the FAC (HOCI) in the water. As the OTO reagent sits in the sample longer, it begins to turn a darker yellow indicating the presence of COMBINED CHLORINE. The end result of the OTO test will indicate the amount of TOTAL CHLORINE in the sample. The problem with this test is most people do not realize how important it is to read the FAC test result immediately after inverting the vial to mix the solution. If you wait more than a few seconds to read the results, the sample will be indicating Total Chlorine not Free Chlorine. The hazard is that you may think the water has an adequate level of FAC and it may not.

Notes on Chlorine Testing

• The small amounts of water in the vials are easily contaminated if the caps are not properly cleaned or if you use fingers instead of the caps to cover the vials.
• If the sample does not turn a color when the reagents are added, it may indicate that there is too high a level of chlorine in the water. That could cause the reagent to be bleached out. If you are using DPD tablets to test chlorine, watch closely at the tablet while it is dissolving and you may see a pink streak of color coming off the tablet but then disappearing into the solution. Never use DPD tablets that are not white in color.
• When testing with an OTO solution, it should give a vivid yellowish/orange color if there is a high level of Total Chlorine in the water. If the OTO does not turn a color, it would mean there is no chlorine in the sample at all.

(Note from Pool Emporium, Inc.: For general testing tips, proper sample collection method, and information required to perform an in-store analysis, be sure to check out Pool Emporium, Inc.'s Test Tips page*!

*Close this window and return to the Table of Contents, and select Test Tips from the "Tips and Troubleshooting" section.)

The information on this page has been provided courtesy of BioLab, Inc. ©1998