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The 7 Most Important Chemical Test Points Needed To Ensure A Safe Pool Or Spa

In this post I will be covering the basics of pool chemistry. In order to do this I will be referring to the AquaChek 551236 7-Way 100 Count Pool Water Test Strips pictured here. If you need to purchase these, please click on the image to the right.

First your test stripes will come with a silica pouch inside which is used to absorb moisture. This is crucial to the integrity of your test stripes. It’s worth mentioning that the strips absolutely must stay dry, or the entire bottle will be corrupted. Even with the cap on, a submerged bottle will be ruined in a short amount of time.

Now that we have covered keeping your test stripes accurate, lets discuss how to test your pool or spas water chemistry. To begin, open the bottle, and preferably after the pools pump has been running for an hour plus, dip one strip into the water, quickly, right at the surface. Be careful to perform these tests away from any return jets, or stationary tab floaters, as it can make the test inaccurate. Immediately look at how the colors change on the strip. After about 30 seconds the reading won’t be accurate and will display higher levels than what is actually in the pool. Now you need to refer to the back of the bottle to view the color chart. The chart listed below is the same information from Aquacheck.

Total Hardness

The first test point on the color chart is called Total Hardness. This refers to the amount of Calcium that is in a given body of water. The acceptable level for this reading is between 250 ppm and 500 ppm. Please click on Calcium in the pool maintenance chemistry to get a more in depth post about what it means for your pool and how to adjust it. Total Hardness does not need to be checked each test, because it doesn’t adjust from week to week. Once I’ve gotten my Calcium to acceptable levels, I only test for it every 3 months.

Total Chlorine/ Bromine

The Second and third test point is Total Chlorine as well as Total Bromine. Most pools use chlorine as a sanitizer, and most spas use bromine because of its resilience to high water temperatures. Your total chlorine is basically the amount of inactive chlorine that’s been used to kill bacteria plus the amount of active chlorine. Its acceptable range is 1 to 5 ppm. Total Bromine is the complete amount of sanitizer and the only reading that is done for spas. It’s good between 2 and 10 ppm.

Free Chlorine

The fourth test point is Free Chlorine, or available Chlorine. This is the Chlorine that is completely able to kill any bacteria in the water. You want this reading to be between 1 and 5 ppm. Please refer to my post on Chlorine for a better understanding of why having both Total and Free Chlorine readings are very important. To learn more about chlorine and how to adjust its level check out the 7 most important steps to pool chemistry maintenance


The fifth test point is pH. This is the measurement of the Acidity/ Alkaline balance of water. Your goal is to have your pH as close to neutral as possible between 7.2 and 7.8. If the reading is low, that means the water is more acidic and essentially more corrosive. If the pH is too high, it’s called basic which leads to problems such as calcification/ scale of your pool and equipment. To adjust the pools pH, take a look at my section on the 7 most important steps to pool chemistry maintenance under the tag pH.

Total Alkalinity

The sixth test point is Total Alkalinity. This reading represents the total of all Alkaline components in water. Usually, Alkalinity readings will map pH readings, but not always. However, maintaining a proper Alkalinity level of 80- 120 ppm will keep your pH from having rapid fluctuations. Low Alkalinity can cause corrosive water, green water, and eye irritation. High Alkalinity can cause cloudy water, scale, and make pH difficult to bring down. For methods of adjusting Total Alkalinity, refer to the the 7 most important steps to pool chemistry maintenance post under the tag Total Alkalinity.

Cyanuric Acid

The seventh and final test point is Cyanuric Acid, commonly called Conditioner or Stabilizer. This is a chemical added to your pool that protects Chlorine from harmful UV rays and should be tested once per month. Without adequate Conditioner levels, chlorine can be zapped out of a pool within ½ hour during hot summer conditions. The acceptable limit is between 30 and 100 ppm. 100 ppm is the legal limit; with the primary reason being Cyanuric Acid is a known carcinogen. Although vital to a pools health, it needs to be maintained at or below the maximum level. To find out more take a look at the The 7 most important steps to pool chemistry maintenance post.

Although a standard pool water test kit, the one with the beakers and colored regents, is more accurate, they take too long for most pool professionals. The AquaChek 551236 7-Way 100 Count Pool Water Test Strips, are more than accurate enough for anyone to perform their routine pool maintenance. You can also purchase the AquaChek 511710 5-in-1 Chlorine Test Strips, which only test Total Chlorine/ Free Bromine, Free Chlorine, pH, and Total Alkalinity. I primarily use these because they are cheaper, but for someone new to pool maintenance, I recommend the 7 test stripes, just so you can become more familiar with those points right from the beginning.

If this seems a little overwhelming, your not alone. It took me a week or two of testing water everyday when I first started cleaning pools before I began understanding how each test factor contributes to water quality long term. For short term pool health, you can simply focus on Chlorine, and pH as a beginner. Those are the two test factors im concered with the most, especially the chlorine levels as that’s an indicator of how sanitary a pools water is, generally speaking. The other test points should be noted, but wont effect the immediate health of your swimming pool. They are chemical factors that can cause issues in the long term if not checked however, so please make sure learn, understand and control all of the test points.

Well I think your ready to begin testing your pools water chemistry. To learn more about water testing and how to adjust the chemical levels in a pool or spa, I suggest reading my post titled The 7 most important steps to pool chemistry maintenance.

Thank you reading the 7 most important chemical test points needed to ensure a safe pool or spa. I hope this helps you on your pool maintenance path. Please read my bio below this post and contact me if you have any questions about the post subjects or suggestions for writing topics you would like to see covered in the Aquablog.

Rhett Blackwell


Mr. Blackwell is  the owner of Aquadoc Pool & Spa Care, LLC.  A leading pool cleaning company in Lancaster, Ca.  He became a Los Angeles County Swimming Pool Maintenaince Technician in 2014.  To find out more about the author click here.  If you would like to contact him go here.

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