04/06/2021 | Swimming Pool & Spa | 8 MINUTE READ

How to Calculate the Chemicals Needed for Your Pool

how to measure chemicals in your pool

No matter the type of pool you have in your backyard, it’s essential that you properly maintain the water quality to ensure that the water is always clean enough to swim in. There are many different chemicals that are required for the pool maintenance, which include a pH increase, chlorine, and shock. When you purchase one of these chemicals, manufacturer instructions will be included to help you determine how much of the substance you should use in your pool. However, these instructions will be meaningless if you don’t know exactly how much water is contained in your pool.

To make sure that you use the right amount of chemicals in your pool, you should use a pool chemical calculator, which will allow you to determine the size of your pool. Once you’ve identified how much water is in your pool, you will be able to effectively determine the number of chemicals that should be placed in the water. It’s important to know how many chemicals are used in your swimming pool because the quality of the pool water can worsen significantly if your calculations are slightly off.

In the event that you place too much chlorine in your pool in an attempt to get rid of any contaminants in the water, anyone who swims in the pool could experience eye and skin damage as well as lung irritation. Exposure to high chlorine levels can also bring about an asthma attack in people who suffer from asthma. If you don’t use a pool chemical calculator, you might make the mistake of not putting enough chemicals in the water. For chlorine and similar chemicals, not using enough of the substance means that too many contaminants will remain in the water. This article offers a detailed guide on how to properly calculate the total amount of chemicals that you require for your pool.

Pool Volume Calculation Basics

pool chemicalsIf you want to properly measure the volume of your pool, there are numerous elements that you’ll need to be aware of. These elements include:

  • A = Area
  • W = Width
  • D = Depth
  • H = Height
  • L = Length
  • V = Volume
  • d = Diameter
  • r = Radius
  • Pi = 3.14 constant

With these elements in mind, you should be ready to complete any type of calculation that will help you determine the volume of your pool. If you want to calculate the cubic volume of your pool, the depth of the pool will need to be included alongside the surface area of the pool. To be certain that you’ve made the right calculations, it’s highly recommended that you divide your pool into separate sections by depth. What this means is that the shallow end of the pool would be calculated separately from the deeper end of the pool.

Keep in mind that a single cubic foot of water consists of 7.5 gallons of water. When you identify the exact cubic footage of your pool, you should then multiply the number by 7.5. This calculation will give you the volume of your pool, which refers to the number of gallons that your pool is able to hold. The method you use to calculate the volume of your pool depends mainly on the shape of your pool. For instance, the technique to calculate the volume of a rectangular pool is much different from the technique used to identify the volume of a round pool.

Rectangular Pool Vs. Square Pool Volume

square pool

If you have a rectangular or square pool, the method you use to calculate the total volume of the pool depends on the layout of the pool bottom. In the event that the pool consists of a single depth, you can identify the surface area for your pool by measuring the width and length. This number should then be multiplied by the depth of the pool to determine the volume in cubic feet. As mentioned earlier, the volume in cubic feet should be multiplied by 7.5 if you want to identify the volume of your pool in gallons. The equation for this measurement is L x W x D x 7.5 = V.

The calculation you use will differ if your pool has a gradual slope. The depth of the shallow end needs to be added to the depth of the deep end, after which the number should be divided by two. This number equals the average depth of your pool. The width and length of the surface area for your pool should be added together. Multiply this number by the depth in order to obtain the volume of your pool in cubic feet. The volume of gallons can be reached by multiplying this number by 7.5.

Some pools are constructed with a distinct drop-off between the shallow and deep ends of the pool, which requires a different kind of measurement. If your pool has variable depths alongside a drop-off, the deep ends and shallow ends of the pool should be considered separate pools. What this means is that you should calculate the volume for both ends with the constant formula that’s mentioned above. This formula is L x W x D x 7.5 = V. When you’ve obtained the volumes for both sections, all that’s required is for you to add the two numbers together to reach the volume for the entire pool.

Round Pool Volume

In order to obtain the volume in gallons for a round pool, you must multiply the Pi number by the radius squared. The radius refers to the width and length of the surface area for your pool, which is also known as the diameter. If the diameter of your pool is 22 feet, the radius squared calculation would be obtained by multiplying 22 x 22. This number is then multiplied by the depth of the pool. With this number in mind, all you need to do is multiply it by 7.5 to reach the total volume in gallons.

Irregular Shaped Pools

It’s important to understand that not every pool has a square, rectangular, or round shape. Many natural pools are designed with completely odd shapes that can’t be classified. Despite the difficulties of doing so, you can still calculate the volume in gallons. However, additional math will be required. To identify the volume of an irregular-shaped pool, think about the calculation that’s used for pools with a drop-off.

In this situation, multiple calculations would occur for each section before adding the number together. The same is true for an irregular-shaped pool. Try to find standard square, circle, or rectangular shapes in the pool. It’s possible that the pool would need to be divided into 5-6 sections. From here, you would use one of the calculations mentioned previously to determine the volume for each section before adding the numbers together.

Uneven Measurements

You may find that the dimensions of your pool don’t add up to a fully rounded number. In this case, the measurement should be rounded off to the nearest foot. Keep in mind that an inch equates to .0833 feet. Multiply the number of inches in your calculation by .0833 to obtain the percentage of one foot. Let’s say that the length of your pool is 24 feet, 10 inches. Multiple 10 x .0833, which gives a reading of .833. Round this number down to .83 before adding it to 24. What this means is that the length of your pool would be 24.83 feet. Once you have reached this number, volume calculations will be more straightforward.

Different Types of Chlorine

different types of chlorineTo fully understand the types of chemicals that you should place in your pool, it’s important that you know about the different types of chlorine. Free chlorine is the total amount of chlorine that hasn’t combined with the chlorinated water in order to sanitize contaminants. On the other hand, total chlorine refers to the sum of combined chlorine and free chlorine. Combined chlorine is chlorine that has already started to sanitize the contaminants in the water.

Chlorine is essential for swimming pools because it’s typically added to the water to kill any contaminants that are present in your pool. By getting rid of contaminants, the water is effectively sanitized, which makes it safe to swim in. If a person swims in pool water that contains high contaminant levels, they have a higher likelihood of experiencing serious health issues. Even though chlorine is considered to be a chemical, it’s mostly safe when used in pool water and is only risky when at very high levels. Knowing the amount of chlorine in your pool water is a key aspect of making sure that the water is disinfected.

Pool Calculators

While you can find many effective pool calculators on the internet, three tools that are easy to use and can help you accurately calculate your pool dimensions include:

Each of these tools is simple and straightforward. If you decide to use the third tool in this list, all that’s required of you is to know the total volume of your pool in gallons as well as the material that the pool is made from. Once you’ve input this information, you’ll receive the exact measurements for many different chemicals that you can place in your pool. These chemicals include free chlorine, pH, total alkalinity, calcium hardness, cyanuric acid, borate, salt, suggested free chlorine, and calcite saturation index.

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Posted by Dominic O'Donnell on April 6, 2021

Sensorex is a global leader in the design and manufacture of quality sensors for water quality and process applications. The company offers more than 2000 sensor packages for pH, ORP, conductivity, dissolved oxygen, free chlorine, chlorine dioxide, UV transmittance and other specialty measurements, as well as a full line of sensor accessories and transmitters. Its expert technical support engineers solve analytical sensor challenges with custom designs and off the shelf products.

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