Pool Chemistry Charts 101 (Pool Chemical Dosage Guidelines)

There are different methods of testing the pool water.

But the best measurement method is of no use if you are unclear which water parameters are essential for pool maintenance.

An overview of the most important basic parameters in the pool can be found here in the pool chemistry chart.

Parameter Level Water Test
Chlorine 0,3 – 1,5 ppm Daily
Bromine 3,0 – 5,0 ppm Daily
Hydrogen Peroxide 3,0 – 8,0 ppm After application
pH-Value 7,2 – 7,6 Daily
Algaecide Manufacturer information Weekly
Flocculant Manufacturer information 2x/Week
Alkalinity 80 – 120 ppm 1x/Month
Calcium 200 – 400 ppm 1x/Month
Cyanuric Acid 30 – 50 ppm 1x/Month
TDS under 2000 ppm Only if necessary

Stick to the pool chemical dosage from the chart, and your swimming pool or whirlpool will stay clean for a long time.

But you still have to learn which factors influence the values in pools and when precise controls of the water make sense.

The following text provides a explanation of the most critical basic parameters for swimming pools.

Tip: Do you want to learn which measuring method is best for pool water testing? Read my detailed blog article about this by clicking on the link.

Alkalinity value in pool water

The alkalinity (also known as acid capacity or acid-binding capacity) interacts with the pH value. It is one of the most important factors in water treatment in pools and whirlpools.

If the alkalinity is not between 80 and 150 ppm, the pH value in the pool will fluctuate strongly. A simple rain shower is enough, and the pool tilts (turns green).

But other problems with the pool water, such as foam formation and lime precipitation, also happen if the value deviates from the ideal.

Therefore, the alkalinity and the pH value must be measured at regular intervals and, if necessary, optimized – The alkalinity in the pool should be measured at least once a month.

A measurement of the alkalinity can be made with test strips, but measurement errors are expected. The better variant is the measuring process with a digital measuring device.

And how is the alkalinity corrected if it deviates from the ideal parameters ​​in the water?

In pool shops, you will find appropriate products that are offered as powders. The powder allows the acid level in the swimming pool to be lowered or raised.

It is best to read the detailed article on alkalinity on the blog and learn how to lower and increase the alkalinity in the pool – click on the link above.

Tip: Before you start optimizing the pH value in the pool, you should always measure the alkalinity first and correct it beforehand to avoid fluctuations.

pH value for clean water in the pool

In addition to the alkalinity, the pH level is one of the most important basic parameters that you should pay attention to.

Running the pool without an optimal pH is impossible and would lead to various water balance problems – For most swimming pools, the ideal level is between 7.2 and 7.6.

A downward deviation from the ideal level leads to acidic pool water. An upward deviation is called alkaline water. Avoid both.

You can read about the exact effects of the pH level in your pool in my blog.

One point you need to know, is that the pH level fluctuates daily and should be measured daily.

Simple water testers are usually sufficient for pool beginners to optimize the pH level. Still, a digital water tester would be an advantage if there are problems with the water quality.

Tip: The pH naturally increases in pools and hot tubs. Therefore, you will need a pH minus for the correction more often than the pH plus.

Determine calcium hardness in the pool

Beginners often neglect the measurement of calcium hardness (also known as water hardness) and wonder later why lime is formed on the walls in the pool and why the filter sand hardens.

This is understandable because testing lime in private pool basins was not possible in the past, and many are not up to date with the latest technology – In our time the water hardness can be read off with test strips.

You should measure the calcium hardness at least once a month.

Ideally, the calcium hardness in your pool is between 200 – 400 ppm. A level in the middle at 300 ppm is considered optimal.

In addition to measuring water with test strips, it is also possible to optimize the water hardness in the pool upwards and downwards with a powder.

You can always find all further information about water hardness in the linked blog post.

Tip: Well, water is mainly calcareous. If you fill your pool with well water, you absolutely have to lower the calcium hardness.

Perfect levels for disinfectants in swimming pools

The pH level, the total alkalinity, and the water’s calcium hardness are just a few of the basic parameters that a pool operator should pay attention to.

The use of disinfectants and their control with water testers is also essential.

But there is a wide range of different disinfectants for pool water with which cloudiness is prevented, and the ideal level is at a different level for each.

As a beginner, you quickly lose track of things, hurting your health.

You should be aware of the pool chemicals that can be dangerous for people and the environment.

Therefore, a professional handling and regular inspection of the water in pools is necessary.

But where are the ideal levels of the most common disinfectants, and how can measurement errors be avoided?

Measure and adjust the chlorine level in the pool

Chlorine is the most frequently used disinfectant in water treatment in private pools.

With its high oxidizing power, bacteria are killed, and the water quality increases.

What is confusing for many newcomers to the pool world is differentiating between the following chlorine.

  • Free chlorine: The actual chlorine used to disinfect the pool water.
  • Combined chlorine: These are chlorine-nitrogen compounds formed due to a reaction with ammonium compounds.

The total chlorine content in the pool is determined from the sum of the free chlorine and the bound chlorine.

So it would help if you had free chlorine to disinfect the swimming pool. The combined chlorine still has a disinfecting effect but is weaker than the free chlorine.

How often do you have to measure the chlorine content in the pool, and how high should the chlorine level be?

Follow the pool chemistry charts below to optimize the chlorine level.

Parameter Outdoor Pool Indoor Pool Water Test
Free Chlorine 0,8 ppm 0,4 ppm Daily
Combined Chlorine 0,2 ppm 0,2 ppm daily

You can measure the chlorine level for the free and total chlorine in the pool with a simple test strip.

Often regular test strips only show the free or the total chlorine level. The measurement results are also not as accurate as with an electronic tester.

When measuring and dosing chlorine, always rely on the objective level (measured with water testers) and not the subjective assessment.

If you want to learn more about the chlorine dosage in the pool, you will find a detailed article on the subject under the link.

Cyanuric acid (chlorine stabilizer)

Compared to other disinfectants, chlorine breaks down quickly. This is why the use of cyanuric acid (also known as a chlorine stabilizer) is necessary.

The cyanuric acid ensures that the chlorine does not break down so quickly due to the sun’s UV rays and that the disinfecting effect lasts longer.

In other words: Anyone who uses chlorine in the pool must also use cyanuric acid.

But this only applies to non-stabilized chlorine. A di-chlorine or tri-chlorine has already been mixed with the acid and consequently stabilized.

If you use di-chlorine or tri-chlorine in the pool, you do not necessarily need to use cyanuric acid.

Above all, the cyanuric acid level must remain at 30 to 50 ppm (mg/l).

But what you should be aware of is that too much cyanuric acid can be bad for chlorine.

  • If the acid concentration is 30 ppm, the proportion of free chlorine falls to 45%.
  • At a concentration of 50 ppm, the ratio of free chlorine falls to 30%.
  • If the cyanuric acid has a concentration above 100 ppm, then the proportion of free chlorine is only 10%.

A regular water test can help optimize the acid concentration – measure 1 to 2x/month the cyanuric acid in the pool water.

In my blog, you will find a detailed article on this topic, where I also explain how to lower the concentration of cyanuric acid.

Measure and balance the hydrogen peroxide in the pool

Hydrogen peroxide is an alternative disinfectant to chlorine in the pool and has become much more popular in recent years due to its high effectiveness.

The hydrogen peroxide is gentle on bathers as it does not produce any byproducts like chlorine, and it is particularly suitable for use in whirlpools.

But here, continuous monitoring of the water parameters is necessary too.

Consumption increases, especially in midsummer, and the usual dose of 2.5 liters per 50 m³ has to be increased.

And how can you test and dose the water in pools for oxygen (O₂)?

So to avoid clouding due to algae growth on sweltering summer days, the content of the active oxygen in the pool is tested with test strips or a liquid test kit and, if necessary, optimized.

You cannot overdose on hydrogen peroxide, so the manufacturer recommend a weekly dosage.

If you use hydrogen peroxide for disinfection, always follow the manufacturer’s instructions, as the oxidizing power can vary.

Tip: The hydrogen peroxide level can only be determined 1 to 2 hours after use.

Suppose no level is displayed during the measurement the next day. In that case, you don’t have to worry – a hydrogen peroxide level of up to 8 ppm is considered unproblematic, according to the statements of chemical experts. Source.

Measure bromine in the pool

Bromine is rarely used because it has a weak effect in water compared to active oxygen and chlorine.

For the article’s completeness, I explain how you should test the bromine in the pool.

Bromine is best measured with drops. The result must be multiplied by 2.25 to get the actual level.

Tip: An increased level for the bromine can be reduced by adding a neutralizer.

With the Pool chemistry charts, you are now well prepared to test the pool water and identify pool water problems.

The next step is to follow the correct order to troubleshoot the pool problem.

Use the search function on the site, and you will find a wide range of helpful articles on pool cleaning.

Have fun optimizing the water quality in the pool!

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Hi. I'm Max Berg. I've been in the pool industry since 2015 and have always felt drawn to water. I'm the author behind swimfool.com, where I share my years of experience in pool maintenance and give helpful tips on keeping a swimming pool or hot tub clean. My tips reduce the costs of water treatment and protect the environment.

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