How To Test Hot Tub Water


If you have set up a hot tub in your backyard, you probably know that to keep it clean and healthy, you need to take care of it. A spa is a huge responsibility. If you treat it right, you will have endless hours of relaxation and enjoyment. But if you neglect it, it will slowly turn into a money dump.

The best and most effective hot tub maintenance practice is testing how acidic or basic your water is as this will determine how many chemicals you will add to it. Spa water is delicate and if you don’t monitor and control its PH, your much-cherished soaking spot will turn into a breeding area for bacteria and contaminants.

Hot tub water testing helps you find out whether your water is balanced or not and do your chemistry accordingly. There is a bonus – it keeps your spa clean and prolongs its life!

But My Water Looks Good, Why Do I Need To Test It?

One of the biggest mistakes most hot tub owners make is to assume that since their water is clear, they don’t need to test it. Now, folks, sparkling water does not always mean that your water is clean or good for bathing. In fact, sometimes those spas that appear clear and inviting could have serious problems.

Okay, having clear hot tub water is a good thing but then sometimes it could be an indication that the PH level is lower than it should be. Sure, your spa will look quite appealing but if the water is too acidic, it will start eating away your equipment and reduce its lifespan. That’s not all; it can cause skin irritation and a burning sensation in your eyes.

But very basic water is not good either. If it doesn’t ruin your swimsuit, it will make your eyes itchy and dry your skin.

The only way to be sure if the water clarity is due to high acidity is through spa water testing. So grab your test kit and get going.

Testing Your Hot Tub

Hot tub water testing can be done in three ways. You can use your normal pool test strip or test kits, or take a sample of your spa water to a professional and let them do it for you. All the same, the process is pretty easy and you don’t even need to be a chemistry genius to get your head around it. As long as you can read numbers and differentiate colors, you will be fine!

Testing Your Spa Water Using Test Strips

Test strips are the most common and simplest way to test your water. Well, they might not be the most accurate but they will give you an idea of how balanced the PH, chlorine, bromine, and total alkalinity are.

  1. Draw a sample of water from your hot tub and put it in a clean glass or plastic container.
  2. Dip a test strip into the container and wait for about 15 to20 seconds.
  3. Hold the strip against the color chart on the strip bottle and compare the colors.
  4. Do this at least once or two times a week. If your spa is used quite often, then you will need to test the water more times than this.

Testing Your Spa Water Using A Test Kit

Most modern hot tubs will come with a test kit. If yours doesn’t, make sure to obtain one even before you decide where to put your hot tub. Read all the instructions written on the kit so that it can be easier for you to conduct the test.

Basic liquid test kits will only check the water for PH and chlorine. To do this:

  1. Draw a sample of water from your spa just as we directed when using test strips.
  2. Add 4 to 5 drops of the reagent you want to test into your sample water.
  3. Wait for about 15 seconds.
  4. Compare the resulting color to that on the container.
  5. Repeat this process once or twice a week to make sure that your water is always balanced.

Having Your Spa Checked By An Expert


Test strips and test kits may not check for everything a hot tub needs to be tested for. It is therefore important to have your dealer check your water once in a while as they can identify a few more things your home testers can’t.

Get a clean plastic or glass container and collect a water sample from your hot tub. Using a clean cap, cover the container up tightly and take it to your spa dealer right away. Do not let your sample wait for too long before presenting it to your dealer as this could result in inaccurate readings.

Once you have had your readings, clean the bottle and keep it safe until your next visit to a hot tub professional. Don’t use your water sample container for any other purpose apart from hot tub water testing.

While getting a professional spa test may seem a daunting task, it gives thorough and more accurate readings than most home tests ever will. A typical home test will only check for sanitizer levels, PH, and alkalinity but a professional will check for additional things like:

Stabilizer: If your hot tub is located outdoor, there is a high possibility that you have used stabilizers at some point during your spa care routine to prevent the sun’s UV radiation from destroying the chlorine in your hot tub water.

Just like other spa treatments, stabilizers should be balanced all the time. If they are too low, you will keep on adding chlorine now and then because most of it will be lost to the UV radiation. Similarly, if your stabilizer level is too high, your spa could go murky and if you don’t know how to fix a cloudy hot tub, then it would be a very ugly site.

Calcium hardness: This is the amount of calcium in your spa water. The reason why we add calcium into our hot tubs is to increase the water saturation so that it doesn’t turn corrosive.

If there is too much calcium in the water, however, scales will start forming and you could end up ruining your hot tub. The only way to find out how low or high the calcium hardness is in your spa water is by having it checked by a professional.

Metals: Where do you refill your water from after draining and cleaning your hot tub? If you don’t know the source of your spa water, there could be a possibility that there are metals in your water that you are not aware of.

Most of the water we use in our households for cooking and laundry has a high concentration of metals and while these may not affect our daily chores, they could have some serious effects on our hot tubs. When dissolved in water metals could stain the surface of your spa or change the color of its water. Only a pool or spa expert can determine whether or not you have metals in your hot tub water or not.

Phosphates: If you don’t want to breed algae in your spa, then you need to keep the phosphates in your water in check, as these are what algae feed on. If you have not shocked your hot tub for some time, then you need to have your water checked by a professional to determine the level of phosphates in it.

This extra hot tub water testing will give you a more accurate picture of the health of your spa water, help you solve potential problems, and make it easier for you to maintain your hot tub chemistry.

To be on the safe side, we recommend that professional spa water testing be done at least once a month. This will keep you on top of things and help you maintain a healthy spa overall.

Globo Surf Overview

Hot tub water testing may sound like a daunting task but as you can see, it is actually a cakewalk. As long as you have your strips or test kits, you can be able to keep your water balanced. Just don’t forget to have your spa dealer check the water for you occasionally, as this will give you a comprehensive report on your hot tub’s overall health.

A clean spa can be achieved with good water chemistry. Get it right from the word go by proper water testing.

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Globo Surf
My name is David Hamburg. I am an avid water sports fan who enjoys paddle boarding, surfing, scuba diving, and kite surfing. Anything with a board or chance I can get in the water I love! I am such a big fan I decided to start this website to review all my favorite products and some others. Hope you enjoy!