Best hot tub test strips and test kits: how to choose
Pick strips that read your sanitizer (free chlorine or bromine), plus pH, total alkalinity and calcium hardness. CDC says to use test strips to check disinfectant and pH[13], and Hot Spring’s own recommended ranges are free chlorine 1–5 ppm, pH 7.2–7.8, total alkalinity 40–120 ppm and calcium hardness 75–150 ppm[18].
One product this answer points to
Listing title: 50 bromine test strips reading pH, bromine, total alkalinity and total hardness.
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What you are testing for
| Reading | Range given by source | Source |
|---|---|---|
| Free chlorine | 1.0–5.0 ppm (Hot Spring owners) · at least 3 ppm (CDC hot tub rash page) | [18][13] |
| Bromine | 4–8 ppm | [13][14] |
| pH | 7.2–7.8 (Hot Spring, CDC Legionella toolkit) · 7.0–7.8 (CDC rash page) | [18][14][13] |
| Total alkalinity | 40–120 ppm (Hot Spring) | [18] |
| Calcium hardness | 75–150 ppm standard; 25–75 ppm with Hot Spring’s salt system | [18] |
The ranges differ a little between sources, which is normal: CDC’s numbers are public-pool baselines, while a spa maker’s numbers are tuned to its own equipment. Follow your owner’s manual if it gives different numbers.
Strips vs liquid (DPD) kits
Strips are quick: you dip, wait and compare the colors to the chart, which Hot Spring describes as giving “a working range” for pH, alkalinity, hardness and chlorine[18]. Liquid reagent kits (the DPD kits below) take more steps and are usually chosen when you want finer readings. CDC’s chemical-safety page also notes that if a reading is off the top of the scale you may need dilution or higher-range strips[15].
How to choose
- Match the sanitizer. A strip made for bromine reads bromine; a chlorine strip reads chlorine. The AquaChek “Red” and “Yellow” listings below make this split in their titles.
- Salt-system tubs need the right strip. Hot Spring warns that calcium tolerances are lower with its salt system, so use the strips made for your spa model[18].
- Check the date and keep the bottle closed. Strips are color chemistry; follow the package instructions for timing and storage.
- Test often. CDC’s toolkit tells public hot tub operators to test disinfectant and pH at least twice a day[14]; home owners usually test less often, but more frequent testing is better in heavy use. Check your own manual for its schedule.
Why bother
CDC links hot tub rash to sitting in a poorly maintained tub and recommends checking disinfectant and pH with test strips[13]. Our pH and alkalinity guide covers what to do with the numbers.
Product lists below are picks, not rankings. We checked that each Amazon listing exists and what its title says; we have not lab-tested any product, and we do not publish prices or star ratings because they change. Match any product to your spa maker’s guidance, and keep the label directions as your final word.
Products worth considering
Spa strips for bromine tubs
Pick a strip whose listing names bromine.
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AquaChek Red 4-Way Spa Test Strips (bromine) Listing title: 50 bromine test strips reading pH, bromine, total alkalinity and total hardness.
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AquaChek SPA 6-in-1 Test Strips Listing title: reads total bromine, total chlorine, free chlorine, pH, total alkalinity and total hardness.
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AquaChek 7-Way Pool and Spa Test Strips Listing title: reads pH, total chlorine, free chlorine, bromine, alkalinity, total hardness and cyanuric acid.
Strips that read free chlorine
Pick one of these for chlorine-sanitized tubs.
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AquaChek Yellow 4-Way Pool and Spa Test Strips (chlorine) Listing title: 50 strips reading pH, free chlorine, total alkalinity and cyanuric acid.
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Leisure Time 45006A Spa & Hot Tub Test Strips Listing title: test strips for chlorine and bromine.
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LaMotte Insta-Test 3 Pool Test Strips Listing title: 50-count strips for free chlorine, alkalinity and pH.
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HTH Spa 86138 Test Strips Listing title: 25 test strips.
Manufacturer strips
If you own a Hot Spring tub, the brand’s own strips are designed around its ranges; confirm which strip fits your sanitizer system.
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Hot Spring Freshwater Spa Test Strips Listing title: Hot Spring Freshwater Spa Test Strips (the brand’s own strips; confirm the strip type matches your sanitizer system).
Liquid DPD kits
More steps, finer color matching, refillable reagents.
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Poolmaster 5-Way Water Test Kit (liquid reagents) Listing title: pool and spa water test kit with liquid reagents.
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Taylor K-1005 DPD 9-in-1 Test Kit Listing title: DPD 9-in-1 pool test kit.
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Taylor K-2005 DPD 9-in-1 Complete Test Kit Listing title: DPD 9-in-1 complete pool test kit.
Questions
How often should I test hot tub water?
CDC’s toolkit says public hot tubs should be tested at least twice a day; for a home tub, follow your spa maker’s manual. More often is better in heavy use.
Do test strips read bromine and chlorine?
Only if the strip says so. Some strips read bromine, some read free chlorine, and some read both; check the listing title and package.
What pH should a hot tub be?
Hot Spring and CDC’s Legionella toolkit both give 7.2–7.8; CDC’s hot tub rash page gives 7.0–7.8.
Sources
- CDC: Preventing Hot Tub Rash
- CDC: Controlling Legionella in Hot Tubs
- CDC: Pool Chemical Safety (applies to pools, hot tubs and spas)
- Hot Spring: How do I choose the right spa chemicals for my hot tub?
This guide summarizes published manufacturer and public-health guidance; always follow your own spa’s owner’s manual. See our disclaimer.