If you own or manage a swimming pool, you may have noticed that there are occasions when you struggle to get an accurate chlorine reading after testing. This can be quite frustrating for any pool owner. Understanding the reasons behind this issue is crucial, and we’ve conducted thorough research to shed light on it.
So, what causes your pool to not retain its chlorine levels? In many cases, the inability of pool water to maintain adequate chlorine levels is due to exposure to conditions that create a high chlorine demand. This phenomenon occurs when the pool water seems balanced and well-maintained but still fails to hold chlorine effectively.
While there are several factors that can contribute to this problem, the one mentioned above is among the most common. In this article, we will explore various reasons why a pool struggles to maintain its chlorine levels and provide tips on how to address the situation. Read on to learn more.
Common Causes of Chlorine Loss in Swimming Pools
Chlorine loss can occur for several reasons. If you’re experiencing this issue, consider the following four common factors that could be affecting your pool’s chlorine levels:
1. High Levels of Contaminants
This is often the leading cause of chlorine depletion. Chlorine works tirelessly to combat contaminants in the water. However, as it battles these impurities, its effectiveness diminishes. Consequently, the greater the number of contaminants present in your pool, the quicker the chlorine will be consumed.
Every pool naturally experiences some level of chlorine loss, but excessive or rapid depletion may indicate that it’s time to assess your water quality. Even something as simple as a collection of leaves or debris at the bottom can absorb chlorine as effectively as oils from the human body. The key takeaway is that all contaminants, whether organic or inorganic, can significantly impact your pool’s chlorine levels. Common culprits include rainwater, leaves, branches, lotions, shampoos, and more.
2. Elevated Temperatures
Excessive heat is another frequent factor contributing to chlorine loss in swimming pools. High temperatures can accelerate water evaporation, which in turn leads to a loss of chemicals, including chlorine. Even on cloudy days, the ambient heat can still affect the chlorine levels in your pool.
As pool water evaporates, the chemical concentration can fluctuate, resulting in a noticeable decrease in chlorine levels over time. Fortunately, this issue can be mitigated by covering your pool when it’s not in use.
3. Direct UV Rays from Sunlight
While we discussed heat, the impact of sunlight on chlorine levels deserves special mention. Experts agree that sunlight and chlorine do not mix well. UV rays from the sun can significantly degrade chlorine, leading to its rapid depletion. This is why it’s advisable to minimize direct sunlight exposure on your pool.
As chlorine molecules are exposed to UV rays, they can break apart, resulting in a continuous decline in sanitizing effectiveness. To counteract this, chlorine stabilizers are available on the market, designed to prolong chlorine’s efficacy in sunlight. However, even with these stabilizers, the sun will eventually diminish chlorine levels. To protect your pool, consider adding a cover or using a pool shade to shield it from direct sunlight. Maintaining Cyanuric acid (CYA) levels between 50 to 100 PPM can also help extend chlorine’s longevity in sunny conditions. Regular weekly testing is recommended, and some chlorine tablets automatically add CYA, gradually increasing stabilizer levels throughout the swimming season. If CYA levels become excessive, backwashing and draining the pool can help lower them.
4. Increased Bather Load
Events such as pool parties often result in a higher number of swimmers than usual. This increase can significantly reduce chlorine levels. If your recent pool testing reveals low chlorine levels, it might be related to a gathering that took place in your pool.
Your pool is typically optimized for a certain number of users—usually just your family. However, when you increase the bather load, additional contaminants are introduced. The chlorine then has to work harder to combat these extra impurities, leading to faster depletion.
Steps to Raise the Chlorine Level in Your Pool
When you discover that your pool’s chlorine levels are low, the most straightforward solution is to raise them. Fortunately, this process is generally simpler than trying to decrease chlorine levels. Follow these steps to restore your pool’s chlorine concentration:
1. Test the Free Available Chlorine (FAC) Concentration
Begin by testing the FAC concentration of your pool. This test will help you ascertain how much chlorine you need to add. If you’re dealing with cloudy or green water, you’ll likely need to shock the pool by elevating the chlorine levels to 10 ppm or higher. However, wait until the levels drop below 5 ppm before swimming again. If the water is clear, raising the concentration to between 1 to 4 ppm should suffice. I recommend using Clorox Test Strips, which come with an app that provides precise readings by simply taking a picture of the strip with your smartphone.
2. Calculate Your Pool’s Volume
Knowing your pool’s volume is crucial for determining how much chlorine to add. If you’re unsure, measure the length, width, and average depth of the pool, then multiply these dimensions together and convert the result into gallons. Remember, one cubic foot equals 7.5 gallons. For convenience, I have a helpful article featuring an easy-to-use calculator for determining your pool’s water volume.
3. Follow Product Instructions Carefully
Always refer to the product label for instructions. This ensures you know how much of the product is needed to achieve your desired chlorine concentration based on your pool’s overall volume.
4. Backwash the Pool Filter
Before adding chlorine, backwash the pool filter to remove any debris. Vacuuming any sediment from the pool bottom is also important. This will help ensure that a significant portion of the added chlorine remains active in the water for a longer duration. Ideally, backwashing and vacuuming should be done prior to adding new chemicals, as this optimizes water circulation and reduces contaminants that could diminish chlorine effectiveness.
5. Add the Required Amount of Chemicals
It’s best to add chlorine in the early evening to minimize degradation from direct sunlight. When adding shock, pour it around the edges of the pool. If your pool has varying water levels, aim to add the shock near the deep end to enhance distribution.
Conclusion
Ultimately, understanding why your pool fails to retain chlorine is only part of the equation. Taking the right steps to restore chlorine levels is equally important. In this article, we explored several reasons for chlorine loss and provided practical solutions to help you achieve your desired chlorine levels.
To fully enjoy your swimming experience, monitoring chlorine levels is essential. By testing your chlorine levels weekly, you’ll develop a better understanding of the best practices to maintain optimal chlorine levels in your pool.