The AquaDoc Water Quality Index (AWQI) Data powered by anonymized SmartSplash water chemistry readings.
Study Summary
Key finding: When pH was in range, it stayed in range within 7 days only 47.7% of the time.
Comparison: Total alkalinity stayed in range 78.9% of the time, and sanitizer stayed in range 71.0% of the time.
Sample size:n = 9,942 consecutive test pairs within 7 days.
What it means: Even after you get pH where you want it, it commonly moves again quickly, so regular checks matter.
Dataset
Coverage: 16,313 water tests across 1,502 customers
Date range: 2025-01-01 to 2026-02-20
Source: SmartSplash water chemistry readings (anonymized)
Method
We analyzed consecutive test pairs that occurred within 7 days. For each parameter, we first filtered to cases where the initial reading was in range, then measured how often the next test was still in range.
pH in range: 7.2 to 7.8
Total alkalinity in range: 70 to 150 ppm
Sanitizer in range: chlorine systems (free chlorine 1 to 6 ppm) and bromine systems (bromine 3 to 8 ppm)
Results
Metric
Stayed In Range Within 7 Days
Sample (n)
pH
47.7%
9,942 follow-up pairs
Total Alkalinity
78.9%
9,942 follow-up pairs
Sanitizer
71.0%
9,942 follow-up pairs
What This Suggests (and What It Does Not)
Suggests: pH is the fastest-moving core reading in typical week-to-week maintenance. If water feels like it is always "almost there," pH volatility is often part of the reason.
Does not prove: this does not prove a single cause of pH movement. Many real-world factors can influence pH between tests, including aeration, bather load, refill water, weather, and product dosing behavior.
Limitations
Observational dataset from real testing behavior, not a controlled experiment.
We did not standardize treatment steps taken between tests.
Some users test more frequently than others, and that can influence the mix of follow-up pairs.
How to Cite This Study
AquaDoc Water Quality Index (AWQI). “AWQI Study: pH Is the Least Stable Reading Week-to-Week.” Data powered by anonymized SmartSplash water chemistry readings. Dataset coverage: 16,313 tests (2025-01-01 to 2026-02-20).
FAQ
Does this mean alkalinity matters less than pH? No. This suggests alkalinity is typically steadier week-to-week, and that steadiness often helps make the rest of water balance easier to manage.
How often should I re-check pH? If your water tends to drift, weekly checks are a practical baseline. More frequent checks can help when you are actively making adjustments.
