Print full article

Best practices for maintenance techs to ensure accurate water test results

A technician should never face the sun, as it will adversely affect their ability to read the results.
A technician should never face the sun, as it will adversely affect their ability to read the results.

Common sense action #5: Work with a water sample that is representative of conditions in the pool as a whole

If a pollster wants to learn if a certain region supports longer school days, but then only asks students, the results will be misleading. If one only asks teachers—another special interest group—the results will still be misleading. In fact, the pollster will follow a strict protocol to make certain their report reflects the opinions of a wide swath of the public.

Water sampling is like polling in that a technician does not want to base their assessment on atypical answers. For instance, water chemistry at the surface of the pool is atypical—it is interacting with the air’s chemistry, evaporation is taking place, and it is where oils and debris float. Water chemistry at a return line, make-up water inlet, or chemical feeders is atypical—treatment chemical concentrations are different in these locations than in the pool at large. Water drawn from corner locations (i.e. dead spots) may not have experienced the same mixing action as open areas.

Therefore, to obtain a representative sample, maintenance technicians should draw water samples from mid-pool away from return lines and from at least elbow depth. The water sample should be tested immediately so its characteristics do not have time to change.

Common sense action #6: Conduct colour-matching tests in natural daylight or with the aid of a daylight simulator

Anyone who has ever walked out of the house wearing two pieces of clothing that looked like they matched, but then once outside noticed they did not has experienced the phenomenon known as metamerism.

Different light sources make for different colours. If a test is designed to be read in daylight (after all, pools are mostly outdoors), artificial lighting (i.e. incandescent and fluorescent) will affect one’s colour perception. Sunglasses can skew a person’s colour perception as well.

The best possible light is outside, facing north, with the sun behind the technician. A technician should never face the sun, as it will adversely affect their ability to match colours.

Common sense action #7: Practice good testing technique and safety

First, store all reagents and/or test kits away from children. When gathering water samples, it is wise to avoid using glass containers since they could shatter. To prevent staining and cross-contamination of tests, remember to rinse out the sample container and the tests cells thoroughly after every test.

Reagent bottles should also be kept tightly capped and never interchanged. Finally, maintenance technicians must remember to wipe up any spills promptly.

To sum it up, to protect a client’s pool and/or hot tub investment, it is not only essential to maintain balanced water, but it is also important for maintenance technicians to be able to perform a wide range of tests precisely. By following the guidelines presented in this article, a maintenance professional will be able to obtain accurate water test results that are required to a health pool and/or hot tub environment for their clients.

Wayne J. Ivusich, BA, MS, CPO,® CPI,™ NSPF®I, is the manager of education for Taylor Technologies Inc., in Sparks, Md. He has been in the pool/hot tub industry for 27 years and has fielded technical questions from health officials, service technicians, distributors, dealers, and pool and hot tub owners about basic and advanced water chemistry. Ivusich, an experienced conference speaker and recognized industry expert, is a Certified Pool Operator (CPO®), a National Swimming Pool Foundation® Instructor (NSPF®I), and a member of the NSPF® Education Committee. He received his bachelor’s degree in 1987 and his master’s degree in 1995 from Towson University in Towson, Md. He can be reached via e-mail at

Leave a Comment


Your email address will not be published. Required fields are marked *