Use real readings to estimate drift/day and predict timing.
This is a planner tool. Record two readings a known number of days apart (same test method). It estimates drift/day and predicts when you'll hit your chosen upper pH.
Result:
Note: pH drift is affected by total alkalinity, aeration, salt systems, CO₂ outgassing, and chemical additions.
Understanding pH Drift in Swimming Pools
pH drift is the natural tendency for pool water to become more acidic or more alkaline over time. Most residential pools slowly experience an increase in pH because carbon dioxide escapes from the water, especially when waterfalls, spas, fountains, or saltwater chlorine generators increase aeration.
Why Monitor pH Drift?
Tracking how quickly your pH changes helps you predict when adjustments will be needed instead of waiting until the water moves outside the recommended range. This can improve water balance, swimmer comfort, and equipment protection.
Common Causes of Rising pH
Saltwater chlorine generators.
High total alkalinity.
Waterfalls, spas, fountains, and other aeration features.
Fresh plaster during the curing period.
Frequent splash-out and refill water.
Tips for Slowing pH Drift
Maintain proper total alkalinity.
Test water consistently using the same test method.
Reduce unnecessary aeration when practical.
Add acid only when testing indicates it is needed.
Track trends instead of reacting to a single reading.
Important Notes
This tool estimates trends only and cannot predict every water condition.
Weather, rainfall, heavy swimmer loads, and chemical additions may change actual drift.
Always verify water chemistry with a reliable test kit before making adjustments.