Using Bleach for Pool Chlorination
Bleach is a popular choice among swimming pool owners for maintaining chlorine levels during the swimming season. I have personally used this method and found it to be one of the simplest ways to keep your pool clean and sparkling. However, there are essential steps to follow for optimal results.
When utilizing bleach as your pool’s primary source of chlorine, it is crucial to test the water’s chlorine levels daily. After determining the current chlorine concentration, you will need to add the appropriate amount of bleach to achieve a chlorine level of approximately 3 to 5 ppm. This process should be repeated daily to replace the chlorine that has dissipated.
The active component in bleach is sodium hypochlorite, which is also the same ingredient found in conventional pool chlorine and in the tablets used for chlorination. When you add bleach to your pool, the sodium hypochlorite increases the chlorine concentration in the water.
During my experience with this method, I aimed to maintain a minimum chlorine level of 3 ppm. The amount of chlorine lost over the course of a day can vary based on factors like temperature, rainfall, and the levels of cyanuric acid (CYA) in your pool. In the peak summer heat, I would typically add enough bleach to raise the chlorine levels to around 5 ppm, anticipating a loss of about 2 ppm by the next day’s test. Conversely, during cooler periods or when I observed a lower chlorine loss of about 1 ppm daily, I would adjust my bleach addition to bring the levels to about 4 ppm. It may take some experimentation, but over time, you will develop expertise in managing this method effectively.
DPD Powder Chlorine Testing
There are various methods for testing chlorine levels in your pool, including test strips and dropper bottles. However, I highly recommend using a DPD powder test kit for greater accuracy. This method allows you to determine your chlorine levels with precision, achieving accuracy within 0.5 or 0.2 ppm, depending on the volume of water used in the test. Relying on the human eye to match colors can often lead to inaccurate readings.
Steps for Using DPD Powder
- Fill the water tube to the 10 ml or 25 ml mark.
- Add one scoop of DPD powder to the tube after adding the water, and swirl to mix. The water will turn pink if chlorine is present.
- Next, using the DPD Titrating Reagent bottle provided with your test kit, add one drop to the pink solution and swirl. Repeat this step until the water changes from pink to completely clear, keeping count of the drops added.
- If you used 10 ml of water, multiply the number of drops added by 0.5 to find the chlorine concentration in your pool. For example, if it took 5 drops to clear the pink solution, the chlorine level in your pool would be 2.5 ppm (5 x 0.5 = 2.5). If you used 25 ml of water, the same procedure applies, but you would multiply the number of drops by 0.2 for a more precise reading. While this method provides a more accurate measurement, it does require more drops, so I generally recommend the 10 ml method for daily use, which gives you a reliable reading within 0.5 ppm.
Adding Bleach to Your Pool
After determining the chlorine levels in your pool, you can calculate the necessary amount of bleach to restore optimal levels. Several factors influence how much bleach you should add, and you can utilize a pool calculator tool that prompts you with a few questions to help determine the required amount. Additionally, I have included a table below that outlines the most common pool sizes and the corresponding amounts of bleach needed to raise chlorine levels.
| Pool Water Volume | Amount of 6% Bleach Needed to Raise 1 PPM |
|---|---|
| 5,000 Gallons | 10 Ounces |
| 7,500 Gallons | 16 Ounces |
| 10,000 Gallons | 21 Ounces |
| 15,000 Gallons | 31 Ounces |
| 20,000 Gallons | 41 Ounces |
| 25,000 Gallons | 52 Ounces |
For instance, if you test your pool’s chlorine levels and find that there is 2 ppm of active chlorine in a 15,000-gallon pool, and you want to raise it to 4 ppm, you would refer to the chart above. It would take 62 ounces of bleach to increase the level by 2 ppm.
Understanding Your CYA Levels
When employing the bleach method to sanitize your swimming pool, it is vital to be aware of your CYA (cyanuric acid) levels. Lower CYA levels can lead to quicker dissipation of chlorine. If your pool has no CYA, you may find that chlorine dissipates rapidly, especially on warm, sunny days, resulting in cloudier water and requiring more bleach, ultimately increasing your costs.
Monthly CYA Testing
Conducting a CYA test is straightforward if you have the proper testing kit, which includes cyanuric acid reagent. You’ll also need a tube with a black dot at the bottom, which will be visible as you add water.
- Fill the provided tube with water up to the 7 ml line.
- Add the cyanuric reagent to the same tube until it reaches the 14 ml line.
- Close the lid and shake the tube vigorously for about one minute.
- After shaking, gradually pour the mixed solution into the other tube containing the black dot, looking through the top. Stop filling once the black dot is no longer visible. The water level at this point will indicate your CYA levels.
By consistently monitoring your CYA levels on a monthly basis and testing your chlorine levels daily, you will ensure a healthy and crystal-clear swimming pool while using bleach as your primary chlorination method.