How To Read A Pool Water Tester? [Ultimate Guide!]

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A pool water tester (PWT) is a device that tests for the presence of chlorine and other chemicals in a pool or spa water system. The test results are typically indicated on a gauge or by an LED light which turns green when the pH is below 8.0 or 6.5, respectively. Many pool water testers are also equipped with a speaker so that you can get alerts in case of trouble.

Since chlorine is a key ingredient in a pool that is safe for swimmers, it is vital to have a PWT in your pool. Daily testing for pH and chlorine is recommended for pool owners to ensure safety. Additionally, regular pool cleaning can remove the excess chemicals that may be present in your pool and make it more suitable for swimming. This, however, should only be done by a professionally trained cleaner who has the proper equipment which can ensure the safety of the pool water.

Difference Between Various Pool Water Testers

There are several different types of pwt with varying qualities and features as discussed below.


One of the most important factors to consider when purchasing a PWT is the size. The amount of water that can be tested at one time is typically indicated on the packaging or the instruction manual for the device. Larger volume options are more suitable for commercial or large residential pools while smaller ones are more suited for single-person households.

Additionally, the amount of tank space that the device takes up is also a key factor to consider since you will need to find room for it in your pool area. Even if you have a very large pool, it may not be possible to accommodate all the different sizes of PWTs.


The amount of available chlorine in your pool determines its safety for swimming. PWTs are typically designed to detect the presence of chlorine at a level of 0.10 ppm which, when combined with pH strips, can be used to calculate the PH down to a 0.05% level or better. Some devices, however, are able to measure chlorine levels down to a 0.02 ppm with the help of advanced technology which makes them more accurate. This allows for more flexibility in pool management.

Additionally, some chlorinators utilize a solid-state sensor which does not require any calibration like the traditional liquid chemical sensors that utilize a liquid reservoir. With these types of sensors, it is not necessary to re-calibrate the device after each use which makes them more reliable and saves time. Finally, the solid-state sensors require half the amount of solvents which are typically found in the liquid chemical sensors and, therefore, are more environmentally-friendly. This makes them a better choice for pool owners who are concerned about their local communities.

Other Chemicals

Apart from chlorine, the presence of other chemicals in your pool determines its suitability for bathing. The most commonly detected chemicals in household pools are nitrates (NO3) and ammonium (NH4+). Nitrates in particular are very dangerous to the water sources since they can create algae in the water which, when consumed by fish and other aquatic life, can create a toxic effect. The most effective way of combating nitrates is through the addition of chemicals which break them down into nitrogen and oxygen. Some devices, however, are able to detect nitrogen down to a 20 ppb level and even lower with the help of advanced technology. This makes them more accurate and flexible in detecting other chemicals that may be present in your pool. As with the chlorine, the presence of other chemicals in your pool can be determined through the use of a pH test combined with a chemical test using a PWT. Nitrates in particular create a problem in pH levels since they alter the acidity of the water. Ammonium also tends to create a higher pH level in your pool (around 7.5-8.5) which can be an indication of a high amount of ammonia in the water. The presence of these chemicals can be harmful to your pool and it is advisable to test for them regularly with a quality PWT.


PWTs come with various features that can make testing for PH levels or measuring the amount of available chlorine more convenient for the user. These features can be found in many different brands which makes them more flexible in solving any problems that may arise. Some of the more common features are as follows:

  • A switch which turns the device on or off
  • A timer so that the device can automatically shut off after a set period of time
  • A backlit display which makes it easy to read the results even in complete darkness
  • A speaker for notifications
  • Various alarms which alert the user if the parameters go out of limits (for example, an alarm may sound if the pH level drops below 6.5)
  • A USB port for data transfer

Additionally, some devices have the ability to display the results on a digital or analog gauge while others have a simple LED indicator light which switches on when the PH or chemical levels are out of limits. The type of indicator light which the device uses is typically found in the instruction manual which you should read thoroughly before purchasing one.


Eco-friendliness should be a main consideration when purchasing anything which is connected to the environment. Since many PWTs are designed to accurately measure the amount of available chlorine in a pool without leaving a significant amount of chemical residue, it is easy to understand why these devices receive high marks in the environmental category. Additionally, many of these devices are designed with recyclable or environmentally-sound packaging and materials which makes them more sustainable options.

Since many people find it difficult to keep track of the chemicals which are present in their pools due to the vast number of different types and brands that are available on the market, a dedicated eco-friendly pool store has emerged as a solution. These stores are known for selling sustainable products which are designed to help with both the creation and management of your pool without risking its safety or cleanliness.


The durability of a product refers to its resistance to damage, wear, or breakage which is particularly important if you plan on using the device actively throughout the year. The lifespan of a product is typically determined by the amount of use that it receives which makes it more important to purchase a durable option which can last for several years of continuous active use. Some of the more durable types of POWs are as follows:

  • Tough plastic or metal construction
  • Stainless steel inner workings
  • Electromagnetic shielding to protect from exposure to water or chemicals
  • OEM-grade materials
  • Power rating up to 300 watts of continuous use

Additionally, if you plan on using the device frequently then look for those that can handle high-volume usage since this will increase the lifespan of the product significantly. The above list of features and considerations are just a small fraction of what you should search for when purchasing a pool water tester. This is a crucial piece of swimming pool equipment which should not be overlooked when planning to upgrade your pool or adding a spa.

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