How to Read Spa Test Strips (Without Guessing)

Test strips are not laboratory gear, but they beat dosing from memory. Used the same way each time, they tell you whether sanitizer, pH, and alkalinity are roughly in range before you throw another handful of chemicals in the tub.

Basic technique

1. Dip the strip in the spa water (away from jets if possible) for the time on the bottle — often one second.
2. Hold level; do not shake like a thermometer unless the brand says to.
3. Wait the stated read time (commonly 15 seconds).
4. Compare in daylight or bright shade. Phone flash can skew colors.

What the pads usually mean

• Sanitizer (bromine or chlorine): aim for the range printed for spas, not pools.
• pH: too low is acidic and can irritate; too high reduces sanitizer effectiveness and can scale.
• Total alkalinity: the buffer that keeps pH from swinging. Fix alkalinity before chasing pH in many cases.
• Hardness (if present): high hardness is common on Michigan wells — expect more frequent drains or scale control.

Common mistakes

• Using expired strips stored in a hot shed.
• Reading under yellow porch lights.
• Testing right after dumping chemicals — wait for circulation.
• Ignoring a dirty filter while “fixing” cloudy water into clarity.

Liquid drop kits are more precise if you get serious; strips are fine for weekly checks. See the testing video for a live demo, and grab strips from the shop.