A log is a series, not one photo
A water testing log is the running history of what you measured, when you measured it, and where you measured it. One result can help, but the pattern across many checks is what shows whether the water is staying in range and whether a process is drifting.
For a simple place to start, keep your notes in one spot and add each reading as you go. If you want a guided place to do that, see the features, try the log sheet, or go back to the home page.
What to write each time
Write the venue, the exact time you checked, the test method, and every value you measured. Add the person who took the reading, any chemical added, and a short note if something looked unusual, such as cloudy water, a missed check, or equipment trouble.
If your site uses Poolsheet, keep the note brief but complete enough that another person can follow the trail later. The goal is to make the log useful for the team and easy to review in one place, including on the guides page.
Strips and kits
This site does not rank test methods. Strips, kits, and meter based checks can all appear in a log if they are the method your site uses. What matters for the record is that you name the method clearly and keep using the same style of note so the series stays easy to read.
If your team is comparing tools, use your own field routine and local requirements to decide what to keep. You can start from the same workflow in Poolsheet and then adapt it to your site without changing the basic habit of logging each check.
Tie it to the model code rhythm
The model code note on the page says when to test, and that timing should shape your log. Build your routine around opening checks, midday checks, closing checks, and any extra checks after a change, then keep the entries in order so the pattern is easy to review.
When your timing is consistent, the log becomes easier to audit and easier to hand off between shifts. If you want to join the waitlist for Poolsheet or keep an eye on what is coming next, visit get the app.
Chlorine and pH windows in the model code
- pH of the water: 7.0 to 7.8 (section 5.7.3.4.1).
- Minimum DPD free chlorine when the venue is not using cyanuric acid: 1.0 ppm (section 5.7.3.1.1.2.1).
- Minimum DPD free chlorine when the venue is using cyanuric acid: 2.0 ppm (section 5.7.3.1.1.2.2).
- Spas: minimum DPD free chlorine 3.0 ppm (section 5.7.3.1.1.2.3).
- Maximum free chlorine: do not exceed the product label (section 5.7.3.1.1.5). This page does not print a numeric chlorine ceiling.
- Cyanuric acid at aquatic venues stays at or below 90 ppm (section 5.7.3.1.3.2). If cyanuric acid is 300 ppm or higher, the venue stays closed until remediation (section 5.7.3.1.3.3).
Sources: 2024 CDC Model Aquatic Health Code, 5th edition (PDF) and CDC notes on operating public pools. Poolsheet is not part of the CDC.
Follow your local health department code. Poolsheet is not a health authority, not a pool operator license, and nothing here means the water is safe. The CDC Model Aquatic Health Code is voluntary guidance, not your local rule.