How to Use a Chlorine Test Kit

Balancing your water and using the right swimming pool chemicals is essential if you want to keep your pool safe and clean all year long.

So, testing your pool water is an important maintenance task for any pool owner, ensuring your swim is the best it can be. Here at 1st Direct Pools, we stock a range of swimming pool chemical test strips and other water testing kits to make establishing which chemicals you need as simple as possible.

What Chemicals can Swimming Pool Test Kits Check for?

When it’s time to balance your water, you’ll generally need to check the levels for:

  • pH
  • Chlorine/bromine
  • Total Alkalinity

There are numerous kinds of kits available that will help you test your water for each of these things. Some may test for all three, while others will test a selection – specialist kits can be used to test for more elements of your water’s chemistry.

Some kits will simply use test strips which can offer a straightforward and instant way to test your water. Many also prefer to use test strips as they are cheaper.

What chemicals do you need for a swimming pool

How to Use Your Water Testing Kit

So, you know you need to test for chlorine, but where do you begin?

We stock many chlorine test kits that test for chlorine in conjunction with other things (usually pH). Solution or tablet-based test kits can be more accurate than strips and, depending on which one you choose, can offer more data.

The exact instructions on how to use your chlorine kit will depend on which particular product you buy. When you buy from a reputable seller, each product will come with detailed instructions on how to use it.

For something like the Chlorine/pH Test Kit Lovibond (Pooltester) or similar test kits, you can use the following guide.

 

Step by Step Guide for Using a Chlorine Test Kit

  1. Remove the lid of your kit and rinse out the compartments with the swimming pool water you want to test.
  2. Fill all compartments to the top with the swimming pool water. Do this by simply scooping up the water from a few inches below the surface.
  3. Add one Phenol Red tablet to the left-hand compartment by tearing open the foil strip. Don’t touch the tablet with your fingers.
  4. Add one DPD no.1 tablet to the right-hand compartment by tearing open the foil strip. Again, don’t touch the tablet with your fingers.
  5. Replace the lid of the pool tester with the arrows pointing towards the printed front.
  6. The tablets will quickly disintegrate. Shake the pool tester several times to help mix the contents thoroughly.
  7. Take the readings by holding the Pool Tester towards natural daylight. Select the nearest colour match against the colour standards and read off the corresponding values.
  8. The reading on the left is the pH value.
  9. The reading on the right is the concentration of free chlorine (mg/l).

 

This is for just one kind of testing kit; browse our range of water testing products to find the perfect product, depending on your requirements.

 

Tips for Using Tablet-Based Testing Kits

Tablet-based tests can be a little more elaborate than test strips. When using these kinds of tests, it can be helpful to remember:

  • Touching the tablet with your fingers can lead to inaccurate results.
  • The colour matching must be carried out immediately after the tablets have dissolved in the water sample.
  • The testing kit’s lid should be thoroughly rinsed out after each test to prevent errors by cross-contamination.
  • Levels of chlorine above 10 mg/l can cause bleaching of the DPD colour. PH readings below 6.8 also produce a yellow colouration, so a reading of 6.8 may be incorrect. PH readings above 8.2 also produce a red colouration, so a reading of 8.2 may be incorrect.
  • Water samples with low readings of Total Alkalinity may give wrong pH readings.

what is chlorine demand

How to Use Chlorine Pool Test Strips

If you prefer to use chlorine test strips, no problem! These are becoming more and more accurate and ensure you can quickly establish whether you need to take any steps to address the chlorine levels in your pool.

When using chlorine test kits, you’ll need to:

 

  1. Hold a strip in your pool water for up to 10 seconds.
  2. Take it out and wait another 10 seconds – the strip will change colour.
  3. Compare the colour to the chlorine colour chart included with the strips.
  4. Adjust the chlorine levels as required.

A child swimming in a clean swimming pool

How to Balance Chlorine in Your Pool

When you’ve established how much chlorine is in your pool (we either kind of test), you will need to ensure it’s at the right level. Chlorine levels should read between one and three parts per million (ppm). If it’s already in the ideal range, great! However, if not, you will either need to:

  • Add chlorine if the chlorine reading is too low
  • Add chlorine reducer if the chlorine reading is too high (you can also wait for the sun to burn it off and re-test).

See our guide to swimming pool shock dosages to find out more about how much chlorine you will need to add to balance your pool water.

 

When do I Need to Test My Pool Water?

When in use, it is generally recommended that you test your chlorine, pH and alkalinity levels once a week. Some experts may also recommend testing your chlorine levels two or three times each week.

If you ever need any water testing kits or pool strips, remember we stock a great range of swimming pool chemicals and products right here at 1st Direct Pools.

For more information about water testing and additional pool maintenance advice, check out our blog, which is full of handy tips and tricks every pool owner should know!