pH Level Testing In Swimming Pool Water Chemistry

pH level testing along with the disinfection testing of your swimming pool, are two of the most important tests that you have to do on your pool water. The reason for this is that you have to maintain a proper pH water balance that will ensure the safety of your bathers and swimmers.

These two swimming pool and spa tests are carried out several times a day according to swimming pool health code standards.

The frequency at which you perform these two tests, is very important. Because the chlorine disinfection and pH levels are the two balancing factors that change the most in swimming  pools and spas. Therefore learning hoe to test pH level in water is an absolute must. 

What Affects Swimming Pool Disinfectants And pH Levels

Your swimming pool and spa water chemistry can be affected by several factors which include:

  • Your bather loads.
  • The sunlight.
  • The rainfall.

Your pH level testing procedure should always be conducted before opening any of your swimming facilities. This will ensure that the conditions of your pool water is safe for swimmers to use at all times. It is also very important that you carry out a pH level testing on your swimming pool or spa water at its highest bather and environmental load conditions.

By doing this, you will ensure that your swimming pool disinfectant system, is keeping up with the bather load demand.

pH Level Testing Procedure For Swimming Pools

When it comes to pH level testing, the procedure is a fairly straight forward one. A solution called Phenol red is used during the test of your swimming pool water sample. There is also the use of pH test strips for this pool water testing procedure. 

There are a couple interfering factors that you have to be aware of though when performing this very important swimming pool test.

These factors can result in the wrong reading doing your pH level testing. They include:

  • High chlorine levels. If your chlorine chemistry levels are too low, it can cause your pH test to come out wrong. Once your free available chlorine is above 5.0 ppm, you will need to neutralize it before you conduct a swimming pool pH test. 

You can achieve this by adding one drop of a chlorine neutralizer...marked R-0007 in your Taylor test kit into your water sample. This is done before you add your pH indicator.

  • High bromine ion. If you have a high level of bromine ions in your swimming pool, again your pH test can be negatively affected. Providing your pool or spa is on a bromine disinfecting system or if you have used a bromine salt (algaecide), it may cause your phenol red to turn bromthyol blue.

 This could result in a purplish color during your pH level testing. This type of reading occurs even if your pH is low.

Understanding The pH Level Testing Scale

The table below should be used when you are conducting a test of the pH in your swimming pool and spas. This is table identifies the pH scale that will help you determine which type of action is required to correct the pH level in your swimming pool. You may have to adjust your pool pH level with either acid or baking soda (sodium bicarbonate), according to your results.

Corrosive WaterBalance Pool WaterScale Forming Environment
6.6 to 7.07.2 to 7.87.9 to 8.4

What To Do After Your pH Level Testing

What you should do when the pH level of your swimming pool water is too high? Apart from testing or checking your pH levels, there are times when you may have to increase or lower your pH levels. In order for you to correctly adjust the pH levels in your swimming pools and spas, you need to conduct an acid demand and a base demand test.

This is an extremely important procedure - which is designed to help you make the correct adjustment to the pH level of your pool water. Once you have done your pH test, you will keep the water sample. At this point, you will add either a base or acid demand solution to determine the amount of acid or soda ash you will need for your adjustment.

The number of drops that it took to reached the desired color is recorded. Upon your results, you will refer to your chemical dosing chart which will tell how much soda ash you have to add.

Meanwhile, if there is a need for you to decrease the pH level of your pool water, then you will add the acid demand solution instead. Once more, this procedure is done drop-by-drop, until the desired color is achieved.

Once completed, record the number of drops that it took to reach the desired color change. Now once again you will refer to your chemical dosing chart.

The chart will indicate how much acid you need to add to your pool water, to safely adjust your pH level. Special note: One very important point that you should always remember here and that is this; your swimming pool pH level is the single most important element in your swimming pool water chemistry.

It has to be at industry standard at all times. Why? Because it affects every other pool chemical balance in your pool or spa water. For this reason,  you and your team must know how to test the pH level in water so that you can always keep the level at its optimum or at industry standards. Keeping a Taylor test kit on hand at all times can help greatly.

Reasons being is that you have to maintain your swimming pool water chemistry through daily swimming pool and spa pH level testing.

pH level testing ensures your swimming pool safety!

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