Obtaining a Proper Water Sample
When my kids were younger, they were heavily involved in the local swim team. This eventually led to involvement in their high school swim team. As any parent who’s been there knows, this means countless meets and hours of volunteering.
Well, my involvement got a little deeper. In addition to the standard daddy duties, I became a USSA referee. Yup, that meant I got to disqualify (or DQ) little 5-year-old girls and boys for doing a backstroke on their tummies. A thankless job…but it had its moments. And the best moments were when someone, other than a swimmer, fell into the pool.
Why on earth am I telling you this?
Well, the sight of a full-grown man falling helplessly into a pool because he wasn’t watching where he was walking is, in and of itself, hysterical! I don’t know why, but for some reason that triggered my weirdly constructed brain to thinking about the importance of finding the right spot in a pool or spa for obtaining a water sample for testing.
Ideally, you should obtain a sample at least 18" below the water’s surface (your elbow is a good stopping point) and away from any return lines. Sunlight can penetrate 4‒6 inches below the surface and possibly affect your test results. Similarly, return lines carry concentrated amounts of treatment and sanitizer that are not representative of the entire body of water; this holds true for indoor facilities as well. If you’re using test strips, follow this same advice when obtaining a water sample. (For best results, dip the test strip into the sample — not into the pool or spa.)
If you want to be even more exacting, you could take a sample from the shallow end and then the deep end and average out the two results. But honestly, who has time for that (geez, sometimes I don’t even have time to grab a cup of coffee in the morning).
Anyway, obtaining your sample water from the appropriate location will help to ensure accurate, reliable, and consistent readings. Just don’t fall into the water while trying to get a sample — because people will laugh and point at you!