How Accurate Are Hot Tub Test Strips?

How accurate are hot tub test strips

As a hot tub owner, keeping your hot tub water fresh and bacteria-free is one of the most common challenges. The warm water coming in touch with human skin makes the perfect ground for breeding bacteria, so you need to test your hot tub water regularly to make sure it’s bacteria-free.

Hot tub test strips are one of the most common ways to ensure that the bacteria and chemical levels in your hot tub water are at optimum levels. When used properly, they can be quite accurate, though don’t expect the same accuracy a spa technician will get from their equipment.

Key Takeaways

  • Hot tub test strips are fairly accurate in measuring water contamination.
  • There are multiple types of hot tub test strips.
  • Accurate results from test strips depend largely on proper usage and handling of the strips.

What are Hot Tub Test Strips?

What are hot tub test strips
What are hot tub test strips?

Hot tub test strips are thin films of strips that have chemicals integrated into them to check the alkalinity, pH, and calcium hardiness of hot tub or spa water. The color of the strip changes based on how much of the above-mentioned factors are present in the hot tub water.

All test strip packs come with a color chart that shows the colors the test strips are going to take depending on how contaminated the water is. Different brands use different colors for their hot tub test strips, so the color charts are not an indicator of the quality of the strip, though strips with lighter colors are easier to read.

How Accurate Are Hot Tub Test Strips?

In general, hot tub test strips are quite accurate compared to their liquid and machine test counterparts. In fact, many hot tub owners prefer using test strips over liquid testing for their hot tubs as the process is pretty simple compared to liquid testing where you have to match the right colored liquids.

However, it’s important to note that hot water test strips are very sensitive, and exposure to the slightest elements like oily skin can significantly affect the result of the strip. That’s why you need to make sure they’re stored in a cool, dry place as well as only use them with clean hands.

Test strips aren’t usually affected by temperature and environment because of the sealed packaging. But if you leave them lying around open for too long then they might get affected, so make sure to pull out only one at a time from the packet.

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Using Hot Tub Test Strips Accurately

How to use hot tub test strips accurately
How to use hot tub test strips accurately

To get accurate results for your hot tub water from your test strips, you need to use them properly, or else you will get incorrect results. Different brands have different instructions, and you have to follow them exactly to get the desired accurate results for your water quality.

Step 1: Dip it correctly

The first step in using hot tub test strips accurately is knowing how to dip them properly in the water. A surprising number of new hot tub owners make mistakes in this very first part of the test which often leads to inaccurate results.

The correct way to gently dip the test strip in the tub wrist deep and gently hold it in that position as specified in the manual. Most strips have to be dipped for only 2-3 seconds. Don’t forget to run your spa for 2-3 minutes before the test.

Step 2: Wait for the result

Make sure to just dip the strip in a stationary position, don’t twirl it around while it’s dipped under water. Once the strip has been submerged for the required amount of time, pull it up and shake it firmly a few times to get rid of the water in the strip. You should be able to see the results in 15-20 seconds. Once you’ve got the results, just use the color chart to match and see how bad or how good the quality of the hot tub water is.

Note that with a hot tub test strip, you don’t get accurate numbers- instead what you get is a range indicator- each shade of the test strip color denotes a range of numbers like 1, 50, 100, etc. The ranges are quite accurate, so when you see brighter shades with higher ranges, it’s usually bad news for your hot tub.

Also, use the right test strip for the right job. Some test strips are made for primarily measuring the bromine levels in the water while others are focused on the chlorine level. Some hybrid test strips are made for determining both, but the general customer consensus is that these strips are less accurate than their single-purpose counterparts.

In an ideal scenario, the test strip results for your hot tub should range between:

  • Total Hardness: 200 – 400 ppm
  • pH: 7.2 – 7.8
  • Alkalinity: 80 – 120 ppm
  • Bromine: 2 – 4 ppm
  • Chlorine: 3 – 5 ppm

If the test ranges show higher numbers than these then you definitely need to change or treat your hot tub water.

Advantages and Disadvantages of Hot Tub Test Strips

Advantages and disadvantages of hot tub test strips
Advantages and disadvantages of hot tub test strips

Now that you know how accurate are hot tub test strips and how to use them accurately. Let’s take a look at some of the common pros and cons of using hot tube test strips.

Advantages of Using Hot Tub Test Strips

  • They’re cheap and easily available.
  • Usually comes in packs of 50, meaning each pack will last you quite a while.
  • The accuracy of test results is comparable to liquid hot tub water tests.

Disadvantages of Using Hot Tub Test Strips

  • Can be easily ruined by weather and other external factors.
  • Since they’re purchased in bulk, it’s often easy to forget the expiration date and get inaccurate results later on.
  • Can’t be used by color-blind people.


1. How long do you keep test strips in a hot tub?

A test strip should be dipped in hot tub water for no more than 2-3 seconds before pulling it out of the water.

2. How many times can you use a test strip?

You can use a test strip only once since the chemicals in the test strip get used up in the reaction.

3. Are pool and hot tub test strips the same?

Yes, pool and hot tub test strips are the same, though some hot tub manufacturers make test strips specific to their products.

Final Thoughts

The luxury of owning a hot tub comes with a few responsibilities, but as long as you follow through with them, you and your family will have an enjoyable time with your hot tub. Using test strips is one of the easiest and cheapest ways of maintaining your hot tub, and should be used at least once a week for best results, so make sure to do so.

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I am Donald M. Beyer and I am backyard enthusiasts. I am a homeowner who has been doing DIY projects in and out of my house for many years. From simple backyard lunches to making an old-school pizza oven in my own backyard, I have a lot of experience in turning my backyard into my and my family’s personal playground.

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