How Often Should You Test Swimming Pool Chlorine?

In general, chlorine levels should be tested at least twice per week. However, the answer to this question depends heavily on how often your swimming pool is used, who uses your pool, and weather events that may introduce a large amount of fresh water into your pool.

The Short, Short Version

Test Chlorine levels at least twice per week. Also make sure to test after heavy use or rainfall, as Chlorine levels have likely been depleted.

Pool chlorine is responsible for sanitizing your pool and hot tub water to make it safe to swim. Therefore, there’s really no such thing as testing pool chlorine too frequently. The easiest way to check your chlorine levels is with test strips. Of course, constant testing is impractical. So, what is the minimum frequency pool chlorine should be tested to ensure free chlorine is at a safe level?

The answer to this question depends heavily on how often your pool is in use, who uses your pool, and weather events that may introduce a large amount of fresh water into your pool.

This article outlines common factors that affect how frequently you may should test your pool chlorine.

Factor #1: Regular Use

At a minimum, you should test your free chlorine 2 or 3 times per week during seasons of regular use. This works out to once every day or two. Testing at this frequency should ensure you are able to keep free chlorine levels at recommended ranges of 2.0 to 4.0+ ppm, assuming no unusual activity or events cause a spike in contaminants.

We recommend testing and adding chemicals in the evenings, when there is no direct sunlight to expedite the interaction of free chlorine with the pool water. This will also help save on chemical costs.

Factor #2: Frequent Use

If you use your pool or hot tub more than once per day during swim season, you may want to increase your free chlorine testing frequency to 4 or 5 times per week. Perspiration contains bacteria that free chlorine will react with to sanitize your pool. The more you use your pool the more perspiration that enters your pool and more free chlorine will be used up.

Increasing testing frequency is necessary to maintain goal ranges of free chlorine day to day. When your free chlorine levels get too low, we recommend using calcium hypochlorite to raise them back up.

Factor #3: Use by Pets and Small Children

If your pool is frequently used by small children or pets, you should test free chlorine more frequently than 2 or 3 times per week. Pet hair contains more bacteria and other contaminants than human hair and skin because pets typically bathe less frequently and get dirtier throughout the day. Pets and small children are also more likely to have bathroom accidents in the pool, including minor ones you may not notice.

Factor #4: Large Gatherings

It is a good idea to test chlorine before and after events that may affect their levels. One such event may be a gathering in which more people than usual use your pool. It’s a good idea to test your chlorine levels before and after this type of event for the same reasons it is a good idea to test if you use the pool more frequently. Perspiration and other contaminants will be introduced to your pool at a higher volume the more people use your pool.

Factor #5: Weather Related Events

Other events that may warrant more frequent testing are weather events. For example, a heavy rainstorm will introduce a lot of new fresh – and potentially acidic – water into your pool. This new water will dilute the concentration of free chlorine, so it is always a good idea to test your chlorine levels after such an event occurs.

Popular posts

The Facts About Pool Algaecide
The Facts About Pool Algaecide

Want to learn more about algaecide? Read on to find out when to add algaecide to your pool maintenance routine and other helpful tips.

Can You Over Shock a Pool?
Can You Over Shock a Pool?

In this quick guide, we’ll answer the question “can you over shock a pool” and unveil the factors to consider when shocking a pool.

The Relationship Between pH and Total Alkalinity
The Relationship Between pH and Total Alkalinity

Maintaining both pH and total alkalinity in your swimming pool is important for keeping your pool properly sanitized and non-corrosive. Total alkalinity is to pH what cyanuric acid is to free chlorine. Total alkalinity stabilizes pH levels. The ideal pool pH level is 7.4 to 7.6. The ideal total alkalinity level is 80 to 120 ppm.

What Should Chlorine Levels Be in Swimming Pools and Hot Tubs?
What Should Chlorine Levels Be in Swimming Pools and Hot Tubs?

The Association of Pool and Spa Professionals recommends free chlorine levels for both swimming pools and hot tubs be kept between 2.0 and 4.0 ppm. However, the Center for Disease Control recommends free chlorine stay above 1 ppm in pools and 3 ppm in hot tubs.