How To Chlorinate A Pool – Standard Chemical Levels

Learn how to chlorinate a pool using standard chemical levels that are safe for public use.

Chlorination is one of the most effective ways to keep pools free of bacteria. Knowing how to apply this chemical appropriately is where the problem lies for many.

If you’re faced with such problems, you’re at the right place. Here, we will provide you with comprehensive methods to get the job done.

You’ll also find information on the many ways a pool can be chlorinated. If you are rather looking at cleaning pools, here is a startup guide.

Why Chlorinate A Pool?

To keep a pool sparkling and free of dirt and germ-causing organisms, treatment will be necessary. Most pools are treated with chlorine. Now, the reason such pools are treated with this chemical compound is due to its sanitizing properties.

The characteristics of this chemical compound include its fast-acting effect in eliminating pool algae, sanitizing the pool as well as helping destroy bacteria.

Although these benefits are obvious, knowing the application techniques and the right amount to add is very vital.

How to Add Chlorine to A Pool

Before a pool is considered due to chlorination, frequent tests must be made. For the best pool sanitation results, a pool will need to be chlorinated as often as necessary.

To apply a chlorine-based sanitizer into a pool, you’ll have to be conversant with certain technical terms such as provided below.

This will be followed by the steps on pool chlorination.

i. Parts Per Million (PPM)

This term refers to the measurement of your chlorine-based pool sanitizer by weight by a million parts (That is by volume) of pool water. This helps you measure just the right amount sufficient enough to sanitize your pool.

You’ll need to frequently test or measure your pool water to find out if it requires an additional round of chlorination.

When treating pools, it is recommended that free available chlorine is kept between 2.0 to 4.0 ppm. This is sufficient to get the work done. Anything less would mean your pool isn’t well chlorinated and can lead to a resurgence of bacteria, and algae among others.

On the other hand, chlorinating pools beyond safe levels can cause harm to swimmers in the following ways; The most common problem associated with excess chlorine in pools is skin irritation. This results in a burning sensation that may worsen.

The other problem arises from chlorine fumes resulting from the evaporation of pool water.

Chlorine fumes get inhaled and get into the eyes as well. This results in significant and discomfort. In very severe cases (though less frequent), it leads to chlorine poisoning.

This can be noticed from symptoms such as mild chest pains, burning throat sensations, nausea & vomiting which could be sudden, mild breathing difficulty, and red skin.

ii. Free Available Chlorine (FAC)

Free available chlorine is a term that simply represents the amount of chlorine in a pool that has not reacted with contaminants.

In other words, this unreacted chlorine is free or available to get the work done in killing or eliminating pool contaminants.

To chlorinate a pool, you’ll need to have all the testing kits necessary to obtain accurate results. Testing for free available chlorine is central to knowing if more chlorination is required or not.

iii. Forms Of Chlorine

To chlorinate a pool, you must know the different forms of chlorine used in pools. These come in different forms such as granular calcium hypochlorite, tablet form calcium hypochlorite, and chlorinated isocyanurates. Others include chlorine gas and liquid bleach.

Using any of these gives you similar results.

Get the form of chlorine available to you and follow the application recommendations provided here. That is the right parts per million volumes of pool water.

iv. Total Chlorine

Total chlorine is simply the sum of both combined chlorine and free available chlorine. Here, the levels of total chlorine in a pool should either be equal to or greater than free chlorine levels.

This is a rule of thumb that helps you maintain the right volume of chlorine in pools.

v. Shock Treatment

Shock treatment refers to the practice of adding a granular oxidizer or powdered form of chlorine such as calcium hypochlorite.

Shock treatment is done to destroy organics, ammonia, and nitrogen-containing contaminants in pools.

  • Steps Involved In Pool Chlorination

Having discussed the above terms relating to pool chlorination, we’ll now shift our focus to the steps of pool chlorination.

This starts with using the test kit and knowing what to look out for.

i. Using A Test Kit

A chlorine test kit for pool chlorination is a must-have if you wish to do a good job. First, there are measurements considered to be safe and conform to safety standards. Knowing what these are will be of tremendous help when using a test kit.

Now, the pool water will need to be tested regularly. It is not a one-off activity but rather something that should be done daily.

In measuring the chlorine balance in your pool, you’re looking out for several things. These range from the total alkalinity, the pH level, calcium hardness, free available chlorine, and the total chlorine levels.

Some test kits are color-coded while others aren’t.

Some of the best pool water test kits include The Taylor K-2006, LaMotte ColorQ Pro 7, Poolmaster 22260, HTH 6-Way 1173, Blue Devil B7550, and the Taylor K1001 Basic. These can be purchased from major online stores like Amazon.

ii. What To Lookout For In A Test Kit

Test kits are calibrated with units to help you identify when a pool needs chlorination among other things. With such calibrations come standard numeric standards set by regulatory authorities for use in pools. These are like health codes that must be adhered to.

We must be also stated that such codes don’t apply to all locations.

In other words, your location or state might have a different set of rules. We will be using the standards set by The Association of Pools and Spa Professionals.

Having explained this far, let’s now see what these codes are as they relate to pH level, calcium hardness, and so on.

  1. Total Alkalinity

The total alkalinity of a pool should fall within a range considered to be safe and acceptable. This is measured in parts per million (PPM). The total alkalinity levels vary for forms of chlorine used.

For liquid chlorine, lithium hypo, and cal hypo (chlorine in tablet form), the total alkalinity range from 80 to 100.

On the other hand, the total alkalinity for gas chlorine, bromine, dichlor, and trichlor should range between 100 to 120.

      2. pH Level

When your test kit shows you a chlorine pH level between 7.2 to 7.8, these are safe levels. Though acceptable, this is not the ideal range. The ideal pH level ranges from 7.4 to 7.6.

Any of these ranges show your pH level is okay.

      3. Calcium Hardness

The calcium hardness of a pool simply measures how hard or soft your pool water is.

When chlorinating, you need to keep an eye to ensure the calcium hardness doesn’t exceed acceptable levels. The unit for measuring calcium hardness is in parts per million (PPM). This should fall within the 200 to 400 range.

      4. Free Available Chlorine

This was explained earlier to mean the part of the total chlorine measurement in a pool that hasn’t reacted with contaminants. This is also measured in PPM and should range from 2.0 to 4.0 ppm.

      5. Total Chlorine Levels

Total chlorine levels are also called total residual chlorine. It is the sum of combined available chlorine and free available chlorine. This should be less than o.2 ppm.


When chlorinating a pool, caution must be exercised. This helps protect from accidents or excess application among other things.

  • How To Apply Chemicals

When applying chemicals to pools, it should be done individually. Avoid adding one to another. Also, keep out of the reach of children. The instructions that come with such chemicals must be adhered to.

By reading such instructions, you are likely to avoid either under-chlorinating or over-chlorinating the pool.

  • Shock Treatment

When using this strategy, consider doing it at night. During the daytime, sunlight might lead to its evaporation. This way, you get to save costs while getting the job done. Shock treatments can be done as often as once every week or two weeks. This depends on how often it’s used. The more often a pool is used, the more frequent shock treatments should be given.

Commercial pools such as those in hotels need shock treatments often. This is due to the higher traffic associated with its use. Shock treatments are also ideal when pool water is murky.

Chlorinating a pool isn’t rocket science once you know what to do. We have attempted to provide you with the basics of pool chlorination. This includes the codes for pool testing among other things.

The entire process of chlorination must be guided by a test kit. Only this allows you to know if and when a pool needs chlorination.

When using tablets for chlorination, a floating container should be used. This is because dropping them directly into the pool ends up staining your liner.

Pool testing should be done as often as necessary. While some recommend it be done daily, doing so twice a week should also suffice.

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