Understanding Test Strips & Water Readings

What your hot tub test results actually mean — and how to interpret them without chasing numbers.

Serving Santa Rosa & surrounding communities

Test strips are a quick and convenient way to check your hot tub water, but they’re only helpful if you know how to interpret the results. This guide explains what each reading means, how the levels affect one another, and how to respond calmly without overcorrecting.

How Test Strips Work

Most hot tub test strips measure multiple water parameters at once. After dipping the strip and waiting for the colors to develop, each pad is compared to the color chart on the bottle.

Readings are typically shown in parts per million (PPM), and small variations are normal. Test strips are best used to identify trends and general balance rather than exact precision.

What the Readings Mean

  • Sanitizer (Chlorine or Bromine): Indicates how much active sanitizer is available to keep the water clean. If this is too low, water can become cloudy or develop odors.
  • pH: Measures how acidic or basic the water is. In hot tubs, a pH range of 7.2–7.6 is generally comfortable and allows sanitizer to work effectively.
  • Total Alkalinity: Acts as a buffer that helps keep pH stable. If alkalinity is off, pH will tend to swing up or down quickly.

Why Order Matters

Because these levels affect each other, the order in which you interpret and adjust them matters:

  1. Start with total alkalinity
  2. Then check and adjust pH
  3. Finally, confirm sanitizer levels
If alkalinity is out of range, pH adjustments often won’t “stick.” Stabilize alkalinity first before making repeated pH changes.

Understanding pH & Alkalinity Together

This video explains how pH and alkalinity interact, why they can feel difficult to balance, and how to avoid an endless cycle of adjustments.

Conceptual explanation adapted for hot tub owners

Avoid Overcorrecting

  • Add only one chemical at a time
  • Allow water to circulate before retesting
  • Expect small day-to-day variation
  • Focus on trends, not perfect numbers

Why Readings Change Over Time

Even balanced water will change. Common causes include temperature shifts, aeration from jets, bather load, and sanitizer use. Regular testing helps catch small changes before they become bigger problems.

Once you understand how to read your test strips, maintaining balanced water becomes far more predictable.

Next up: weekly and monthly water care routines.