How to Test Pool Water

Besides basic maintenance work on pumps and filters a pool owner more importantly needs the knowledge on how to test pool water because once you take the pool covers off, open your pool, and start performing basic water tests on the swimming pool like pH, total alkalinity, calcium hardness, and of course chlorine residuals the game is on. After 35 years of keeping an inground pool, I learned the best ways to test one. What are the best ways to test pool water? 

  • Use a reliable pool test kit
  • Change reagents/strips per season
  • Sample 18″ down at the deep end
  • Sample & test in am/before the start of the day
  • Sample & test in pm/at end of the day
  • Test sample within 5-10 min. of collecting
  • Be consistent when collecting samples & testing
  • Clean comparators/cells between test

Pool water testing is always done at a minimum of 2 to 3 times per week for pH and chlorine levels with a good reliable pool testing kit especially if the pool & spa owner is new to maintenance and how usage and temperatures fluctuate levels during the season.

How to Test Pool Water


Testing pool water shouldn’t be done after your chores at the swimming pool are finished instead they should be done before pre-skimming, backflushing, or any maintenance job that is on the list for pool care that day. That way testing water in your pool is first on the list.

Chlorine & pH levels on pool water should be done on a schedule 3-4 times per week depending on the size, gallons, and usage of your swimming pool. The acid and alkalinity levels of the pool water are extremely important.

Learning to test pool water and sampling your pool water should be part of your maintenance pool care learning curve if you are a serious pool owner. Depending on the size of your swimming pool should dictate how much time and money you put into pool testing or monitoring equipment. Understand what makes pH (the acid and alkalinity) and chlorine work together.

Testing the chemistry of the pool water can not only keep your pool looking good but save you a ton of time and money. It’s also a great way to understand the science of your Salt or Freshwater pool.

Test your pool water sample levels either before the pool opens at the start of the day and is empty or after the pool is closed at the end of the day and is empty of all swimmers so that any chemical adjustments that need to be made can be made and have some time to react before the things get busy again.

Maintaining a proper chemical balance of chlorine & pH will prevent bad things from happening and keep you in the swimming pool water not above it or at the Swimming Pool Supply Store. Work out scheduled maintenance time that will fit with yours and be consistent as best you can.

If there are situations (and there will be that warrant more testing) like using cleaners after heavy storms, hot weather, or heavy usage and of course, time then always test pool water based on the event. Chlorine and pH are the result of what is chemically happening after the source of a change.

How to Sample Swimming Pool Water

To sample swimming pool water, use a clean plastic container and hold it at elbow depth. Submerge the container, then turn it upside down to collect the water sample. Avoid sampling water near return jets or skimmers to ensure an accurate representation of the pool’s water chemistry. Follow these tips:

Sampling Pool Water 

  • Buy a good reliable Pool Water Testing Kit and Reagents (for an Inground larger pool I would go a few extra bucks)
  • Read pool water Instructions carefully
  • Store Pool Water Test Kits and Test Strips in a cool dry area away from the pool
  • Sample test water from the pool in the AM before the kids go in (after the filter has been running) or
  • Sample test water from the pool in the PM after the kids are done for the day (before adding chemicals)
  • Sample pool water in the deep end of the pool (dip the tips approximately 18 inches down)
  • Run the pool’s water test sample right away or within 5-10 minutes (keep out of Sun)
  • Don’t touch water samples-your fingers have acid on the skin which affects the results
  • Be consistent with pool water test sampling and testing levels (Where and When)

Water Testing for Total Alkalinity and Free Chlorine Liquid Test


Use these Pool Water Parameters:

  • pH: 7.4 – 7.6.
  • Chlorine: 1.0 – 3.0 ppm.
  • Total Alkalinity: 80 – 140 ppm.
  • Calcium Hardness: 200 – 400.
  • Cyanuric Acid: 25 – 50 ppm.
  • Total Dissolved Solids: 500 – 5000 ppm.

Please Tell Me, How Do I Read a Meniscus Accurately?Try not to touch any sample or test strip with your fingers. Believe it or not, your fingers can change the test results if they come in contact with the solution, caps on the comparator, reagents, or color strip which will lead to erroneous results. Pool water sampling should be clean and consistent for the best results. Make sure to fill the water test to the meniscus level on the mark on the column for liquid kits.

Shake the liquid test Reagent before adding the drops to the sample cell or comparator. Cap the chemical reagent and return it to the test kit keeping it away from UV sunlight around the pool area. 

Hold a white background at the back of the color comparator for a clearer view and better contrast between eyeballing comparisons when the sun is shining at the side of the pool.

Wait appropriate time for chemical addition to work before adding more to the swimming pool. Know your swimming pool turnover rate in hours and the dimensions of your pool. 

When using Test Strips, take an isolated sample of the pool water in a clean container to be tested instead of trying to dip the strip into the pool itself. The strips always break down and contaminate by folding up then bleeding over the pads and touching parts of your skin. I don’t like them for pool care but you may find them better for pool water testing because of the ease of using them in smaller situations.


Swimming Pool Water Test Strips


How to Read a Pool Test Strip Color Chart | Clorox® Pool&Spa™
              Pool Water Test Strips
Pool Chemical Levels and Chemical Charts - In The Swim Pool Blog
                        Pool Water Testing Chart

When looking for good reliable Pool water test Kits you need one that is easy to read and can perform the standard pool test with enough reagent for the season.

I always recommend liquid reagents for pool water testing because of their more exact results using the Drop test at the very least for pH, Chlorine, and Total Alkalinity levels pool test in ppm measurement.

Good Pool kits come in polyethylene carry cases that protect the chemicals and contain several tiny plastic bottles filled with reagents depending on the size kit, you may have two or more reagents.

The bigger the pool the more elaborate your Pool Water Test Kit should be. Make sure and figure out the configurations of your pool and read the labels on any chemicals you buy that give the details on how many chemicals to use to get the appropriate ppm readings you are looking for.

The pool test kits and reagents should always be stored in a cool dry area. Buy replaceable reagents every season when you buy pool chemicals at the pool supply store always check the expiration date and always buy from a dependable dealer instead of the Home Improvement centers which tend to store chemicals, especially chlorine too long. Pay the extra buck and get fresh supplies every year. You’ll be happy that you did. Reagents for a pool water test have expiration dates.

Pool Water Testing Strips are the easiest and can be good if you are operating a smaller spa or above-ground pool that doesn’t demand a whole lot of testing, except for pH and Chlorine water test levels in ppm. They can be reliable and close as long as they are used properly. I don’t use them because they are easy to contaminate and harder to keep around an inground pool.

Testing Pool Water in Small Pools


Testing pool water in small pools follows similar principles to larger pools but may require smaller testing quantities and adjustments due to the reduced volume. Here’s a guide:

  1. Choose appropriate testing kits: Opt for test strips or liquid test kits designed for smaller pool volumes.
  2. Follow instructions: Read and follow the instructions provided with your testing kit carefully.
  3. Collect water sample: Use a clean container to collect a small sample of pool water.
  4. Test parameters: Test for essential parameters like pH, chlorine, alkalinity, and possibly others like cyanuric acid or calcium hardness, depending on your pool type.
  5. Adjust as needed: Make any necessary adjustments to the water chemistry based on test results. Use smaller quantities of chemicals proportional to your pool’s size.
  6. Maintain records: Keep track of your testing results and chemical adjustments to establish a regular maintenance routine.
  7. Regular testing: Test your small pool water regularly, ideally at least once or twice a week, to ensure consistent water quality.
  8. Consider environmental factors: Small pools may be more susceptible to rapid changes in water chemistry due to factors like temperature and sunlight exposure. Adjust testing frequency as needed.

By following these steps, you can effectively test and maintain water quality in small pools, ensuring a safe and enjoyable swimming experience.

For a smaller pool with fewer gallons, they might be what you are looking for. I would never use them for an inground swimming pool. Testing for critical pool tests like Total Alkalinity and Free Chlorine just won’t give you the best solid results using Pool test strips the way liquid tests would.

Pool test strips are also known as colorimetric pool test kits. They are simple to use and inexpensive, but the results are not as accurate as a liquid or digital test kit. This assessment consists of dipping the strip into a pool water sample and then matching the color to an included chart. Use them for pH(brown)and Chlorine(yellow) tests. I find strips questionable for measuring total alkalinity.

Accuracy levels become a problem if more than one person is testing the water because the color results on the strip can be interpreted differently depending on the person and their subjective opinion. These test kits normally analyze up to seven factors with just one strip.

Testing Swimming Pool Water Liquid Test Kit


Liquid pool water test kits are also called titrimetric pool test kits. These kits are the most commonly used test kits because of their affordable price and high level of accuracy. However, liquid test kits may be the most difficult to use because they require the user to collect a water sample of pool water, and then apply the correct number of drops of the pool water to determine the balance of chemicals and pH in the pool water.

The pool water test kits typically come with two to seven dropper bottles, each with a unique reagent to analyze the swimming pool water. If you have an inground pool and you need to run a test like pH, free chlorine along with TA Total Alkalinity, Acid, Calcium Hardness levels, or other stringent parameter control testing. This pool water testing kit is what you need.

When testing your pool’s water sample with a liquid reagent kit,  just fill the included vials or comparator with pool water test samples from your chlorine or saltwater pool, and then add the liquid reagent according to the manufacturer’s instructions. Keep pool water test reagents out of the sun and shake them before use. Your fingers have acid on them and can easily contaminate the Acid and Alkalinity level on the strip.

Counting the drops as you mix the reagent with your test water samples, the samples will change color and give out a reading. After the test is completed rinse out the comparator. The reagents will stain the plastic and give faulty readings especially after you shock the pool with chlorine. Giving you false reading all season long.

You can’t trust the results you may get with them. You won’t save any money most likely you’ll get bad readings that will screw up the pool water and be back up the pool store looking for chemicals to fix everything. Been there Done that!

How to Add Pool Chemicals to a Pool After Test


  • Always read and follow the chemical’s instructions to ensure the safe use of chemicals
  • Wait for pool water results after adding chemicals before testing pool water again
  • Wear appropriate protective equipment, especially eye protection
  • Handle pool chemicals in a well-ventilated area
  • Use separate, clean metal or plastic measuring cups for each chemical to transfer or measure chemicals
  • Protect pool chemicals from moisture and humidity even water such as a cup of water or coffee
  • When needed always dilute chemicals by adding them to water, especially muriatic acid, never the other way around, Never add acid to H2O
  • Never mix different pool chemicals
  • Do not put spilled pool chemicals back into their containers
  • Do not smoke when handling pool chemicals
  • Do not expose pool chemicals to heat or flames


Best Swimming Pool Water Liquid Test Kit

Taylor Service Complete Pool Water Test Kit K-2006C 


If you want to use what I use this is the very best swimming pool water test kit on the market Taylor has been around for a long and I have used them at work for wastewater and water treatment and at home for pool water testing on my inground swimming pool.

The pool water test kit is capable of running Tests for Chlorine, Free Chlorine, Total Chlorine, pH, Acid and Base Demand, Calcium Hardness level, Iron, Copper, Total Alkalinity, and Stabilizer levels in ppm. Always calculate the gallons of pools and follow directions.

The 2006C kit uses 2 oz. reagents with titrants to improve accuracy, including a printed color comparator, waterproof instructions, treatment charts, and a waterproof chemistry guide. It’s very accurate and easy to use.  I have been using this for years. This is the Best Water Test Kit!  Taylor Service Complete Pool Water Test Kit K-2006C 

If you don’t want to mix reagents there are Digital electronics- which are the convenient new generation in pool water testing and monitoring, specially built for Saltwater pools where salinity (salt) is an important measurement.

They are smart instruments and some have built-in meter calibration, temperature compensation, and Salt NaCl conversion. Probes have a working life and some need re-calibration which can be a hassle.

Stick with basic pool water test reagents that can be refilled at the nearest swimming pool center. If your reagents are left in the sun then change them the sun’s UV rays will destroy them and you will be working with bogus results. If they are expired from last season then buy new ones.

Liquid testing is the way to go for swimming pool care if you want to keep on top of your swimming pool water testing every year. Whether your swimming pool is inground or aboveground they all work the same way. Testing pool water is more than pH and chlorine testing and is crucial to know where the chemical balance is at all times and adjust it before something goes wrong.

Testing Swimming Pool Water Tips


Testing swimming pool water is essential for maintaining its quality and ensuring a safe swimming environment. Here are some tips:

  1. Regular Testing: Test your pool water at least once or twice a week, especially during the swimming season or after heavy pool use.
  2. Follow Instructions: Read and follow the instructions provided with your testing kit carefully to ensure accurate results.
  3. Test Multiple Parameters: Measure key parameters such as pH, chlorine/bromine levels, total alkalinity, calcium hardness, and cyanuric acid to maintain proper water balance.
  4. Use Clean Equipment: Use clean containers and tools to collect water samples and perform tests to prevent contamination.
  5. Test at the Same Time: Test your pool water at the same time of day to ensure consistency in results.
  6. Take Action Based on Results: Adjust chemical levels as needed based on test results to maintain balanced water chemistry.
  7. Keep Records: Keep a log of your test results and chemical adjustments to track trends and maintain a consistent maintenance schedule.
  8. Consider Environmental Factors: Be aware of environmental factors such as weather, sunlight exposure, and pool usage, which can affect water chemistry and testing frequency.
  9. Calibrate Equipment: If using digital or electronic test kits, calibrate them periodically to ensure accurate readings.
  10. Seek Professional Advice: If you’re unsure about test results or how to adjust chemical levels, consult with a pool professional for guidance.

By following these tips, you can effectively test and maintain your swimming pool water, ensuring a clean, safe, and enjoyable swimming experience for you and your family.

Stick with basic pool water test reagents that can be refilled at the nearest swimming pool center. If your reagents are left in the sun then change them the sun’s UV rays will destroy them and you will be working with bogus results. If they are expired from last season then buy new ones.

Liquid testing is the way to go for swimming pool care if you want to keep on top of your swimming pool water testing every year. Whether your swimming pool is inground or aboveground they all work the same way.

Testing pool water is more than pH test and chlorine test and is crucial when testing pools to know where the chemical balance is at all times and adjust it before something goes wrong. Always sample swimming pool water the same way, around 18 inches down at the deep end of the pool. Always test pool water before adding chemicals  Never touch the pool test strip or solution in a pool test.

Do Digital Pool Test Kits Work


Yes, digital pool test kits work and are becoming increasingly popular due to their convenience and accuracy. These kits typically use sensors or probes to measure various parameters such as pH, chlorine, alkalinity, and sometimes additional parameters like cyanuric acid or calcium hardness.

Users simply dip the probes into the pool water and receive digital readouts of the results, often displayed on a handheld device or smartphone app. Digital test kits can provide rapid and precise measurements, making pool maintenance easier and more efficient. However, they may be more expensive upfront compared to traditional test kits and may require occasional calibration to maintain accuracy.

Liquid test kits offer a wide range of testing options over regular pool test kits and test strips. However, they require precision and time when adding liquid reagents. Otherwise, you could get inaccurate results.
Digital readers, on the other hand, are fast, accurate, and great for anyone who has trouble reading color. However, they’re more expensive than other types of pool test kits.
Digital meters use metallic probes and internal software to measure various aspects of your swimming pool water. They will measure pool water sanitizer levels, pH, and TDS or Total Dissolved Solids in swimming pool water, but few will test pool water for TA or CH levels as well.

Sometimes these meters test pool water for Total Alkalinity and Calcium Hardness ppm in pools, tend not to change very quickly or very often, and a separate test every few months might suffice.

Photometric Scanners use an internal spectra-photometer and powerful software for pool water testing to calculate precise readings.

You simply insert a sample of pool water or hot tub and a liquid or tablet reagent into the device, and the hand-held scanner reads out the results in parts per million (ppm) level. They will test your pool for a wide variety of pool water balance parameters, and this type of digital pool water tester also computes the recommended amounts of chemicals to add to your pool if an adjustment is necessary.


What is the best Swimming Pool Return Jets Position?

At the Deepest End of the pool
turn the Return Jets (eyeballs) located on the pool walls angled down toward the bottom of the pool at a 45° angle

In the Shallow End of the pool
turn the Return Jets clockwise to about 8 o’clock at a 45° angle so the return water to the pool is mixing in a circular motion. ………………………………………………………….. Read more


JimGallloway Author/Editor


Pool Operation Management-Water Testing 

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