4.3 Routine testing, recordkeeping & troubleshooting

Routine Operator Testing

Testing turns invisible water chemistry into numbers you can act on. The two most critical parameters, disinfectant (free chlorine or bromine) and pH, change fastest and must be tested most often. Under the Model Aquatic Health Code (MAHC) and most local codes, operators test free chlorine and pH at least every few hours (many high-use venues test hourly at peak bather load), while the more stable parameters, total alkalinity (TA), calcium hardness (CH), and cyanuric acid (CYA), are checked weekly. Always follow the stricter of the MAHC or your local health code.

Testing frequency scales with risk: the busier the pool and the warmer the water, the faster chlorine is consumed and the more often you must test. A calm indoor lap pool at dawn may hold its numbers for hours, while a crowded outdoor pool on a hot afternoon can burn through its free chlorine in under an hour. Never assume yesterday's dose is today's reality; test before you trust.

Testing Frequency and Targets

Use a reliable kit: DPD color-matching for routine chlorine and pH, or FAS-DPD titration when you need precise high-range chlorine readings. Draw the sample at the correct depth (elbow-deep, away from returns) and replace reagents before they expire.

Acting on a Test Result

A test is only useful if it drives an action. When free chlorine reads low, add sanitizer and retest before reopening; when pH climbs above 7.8, add acid in measured doses and recheck, because overcorrecting can crash the pH and make the water corrosive. Combined chlorine (total chlorine minus free chlorine) above roughly 0.2 to 0.4 ppm signals chloramine buildup and calls for breakpoint chlorination, raising free chlorine high enough to burn off the combined fraction. After any chemical addition, let the water circulate for at least one full turnover before you retest, so the reading reflects fully mixed water rather than an undissolved slug of chemical sitting near the feeder.

Recordkeeping and Logs

Codes require operators to keep a written or electronic log, and inspectors will ask for it. Each entry should capture:

• Date and time of each test
• Free chlorine, combined chlorine, and pH readings
• TA, CH, and CYA on their weekly schedule
• Flow-meter reading and filter pressures
• Chemicals added (type and amount)
• Bather counts and any fecal or vomit incident and closure records

Good logs prove compliance, reveal trends before they become failures (for example, a slow pH climb), and guide the next operator's decisions. Retain records for the period your jurisdiction requires, often 1 to 3 years.

Water-Clarity Standard

Clarity is a safety standard, not an aesthetic one: a swimmer in distress on the bottom must be visible to lifeguards. The universal rule is that the main drain, or a black disk placed at the deepest point, must be clearly visible from the deck. If the main drain is cloudy or invisible, the pool must be closed immediately until clarity is restored, because a submerged victim could go unseen.

Daily Opening and Closing Checks

Beyond scheduled chemistry, build fixed opening and closing routines. At opening, confirm the main drain is visible, check that the drain covers are intact and securely fastened (a broken or missing cover is a suction-entrapment hazard), verify the flow meter and pump are running normally, and empty the skimmer and pump baskets. At closing, log the final readings, note the water level, and record any chemicals fed by the automated system. These bookend checks catch equipment problems and safety hazards before they escalate into a closure or an injury.

Operations Troubleshooting

When something goes wrong, work from symptom to cause:

• Short filter cycles / rapid pressure rise: high bather load, incoming debris, or scale forming on the media from poor balance; check chemistry, pre-clean the water, and confirm you are not exceeding the filtration rate.
• Low flow at normal filter pressure: clogged pump or skimmer basket, a closed or throttled valve, a suction-side air leak (look for air in the pump strainer), or a low water level starving the skimmers.
• High chlorine demand (chlorine will not hold): heavy bather load, high combined chloramines, sunlight with low CYA, algae, or organic contamination; shock or breakpoint chlorinate and verify stabilizer.
• Cloudy water: poor filtration, high pH or scaling, or high combined chlorine; correct the balance, clean the filter, and check turnover.
• pH drift upward: aeration and high alkalinity; pH drift downward: overuse of acidic sanitizers. Adjust and recheck alkalinity.

A disciplined loop of test, record, adjust, retest keeps the pool safe, compliant, and open. Most violations trace back to a skipped test or an ignored log entry, so treat routine testing and documentation as the operator's most important daily duty.