Many pieces of equipment are needed to keep the swimming pool clean at all times with the best pool vacuums out there.

So here is a guide on **how to select the correct filter size for your swimming pool.**

Keeping the swimming pool clean is not an easy task and doing it manually is almost always not enough.

You need to get help from the different appliances for cleaning the pool and backwashing the pumps.

The pool pump, for example, is a very important piece of equipment as it **circulates the water** and the chemicals in it.

However, you need a line of defense before letting the water in it.

That is where the pool filter gets to do its job and prevent the pool pump from clogging.

The pool filter is responsible for holding the debris from the pool’s water to not get in the pump.

However, you cannot just buy the first pool filter that you see, as it may not fit in your swimming pool.

There are some **standard openings** in the pool that need to be accounted for beforehand.

Here, we have a guide that you can follow to make sure you buy the right pool filter and avoid spending money for nothing. Follow the guide so you can figure out which filter to buy.

## P**OOL FILTER CALCULATOR**

The following guide includes calculations as we tried to be as detailed as possible. So if you already know the process itself, you can be more accurate with the calculations.

There are also some benefits if you** purchase** your swimming pool instead of building it. The calculators need most of the dimensions of the swimming pool itself, so it is good to know.

The first steps are about getting your swimming pool dimensions, so get your measuring tape ready and follow the guide below to get the right pool filter size properly.

You can use calculators like the one from poolchemicalcalculator.com and the one from poolresearch.com for an effective filtration area calculation.

**Step 1: Find The Surface Area And Volume**

The first thing you need to do is find the surface area of your swimming pool and then try to calculate how much water it can hold to know how to adjust the pump and filter’s power.

Swimming pools come in all shapes and sizes, but there are** two common shapes** for pools. One is the rectangular pool most of us have, and the other is a round pool or oval-shaped pool.

Depending on the swimming pool that you have, you need to make sure that you calculate the size correctly. Here, we have two simple formulas for how to calculate the size of the two pools.

Rectangular swimming pools are pretty easy to calculate as you only need their length and width measurements. Once you get the measurements of the **length and width**, multiply them.

If you have a round pool, it would be a little trickier to calculate, but it does not take much if you have your calculator for a simple yet effective filtration area calculation.

First, get the length of your pool or the radius of it.

The** radius** is half across the round swimming pool. Multiply the radius by itself and then multiply the result to pi; that is the basic calculation to know the circumference of your round pool.

The benefit of purchasing the swimming pool is that the company usually provides the swimming pool dimensions, so you do not need to do all the calculations yourself.

**Step 2: Find The Maximum Volume Of The Swimming Pool**

You will then need to find the swimming pool’s volume to know how much water it can hold. This is an easy calculation, and most of the time, it is provided when you purchase the pool.

After finding the volume of your swimming pool, find out how much water can move through your filter to ensure that you get the right one.

This is called the **flow rate **of the pool pump and can be lower for most above-ground pools. Above-ground pools have delicate pool constructions so pumps are usually weaker for them.

You do not need to depend on one swimming pool as the flow rate can change from one pool to another. Keep that in mind when calculating the volume and the flow rate of the swimming pool.

To find the volume of your swimming pool, you need to get the **maximum volume **of the pool provided by the company upon purchasing the pool. Divide the number by 360.

The answer will tell you the number of gallons that the filter can take in a minute.

That is how much water goes through the filter, so make sure that you get the filter that can handle it.

Even with the volume alone, you can refer to most charts on the internet for the filter that you need. These charts give you the filter used in most pools with the same volume as yours.

Given, these charts are not the most accurate but they can really help. If you do not trust the charts, then proceed to see how to accurately see the right filter for your pool.

**Step 3: Know Your Pool’s Turnover Rate**

Aside from the amount of water that passes through the filter every minute, you also need to establish your pool’s turnover rate. It is to know how long it takes for the water to circulate.

This is mostly about your pool pump’s power, but it is important because you need to know how long you will need the filter and the pool pump to work properly and keep the pool clean.

Most of the time, municipal codes require your pool pump to circulate the water in the swimming pool **at least twice** within 24 hours. So take a look at your local codes.

That would not be a problem since we have powerful pool pumps that can circulate the water once within **8 or 10 hours.**

This is also usually provided on the pump’s label.

The minimum for circulation of the poo’s water is at least once every 12 hours. However, we have more powerful pool pumps now, so know how long it takes for your pump to circulate.

**Step 4: Get The Correct Pool Filter Size**

After calculating all the needed dimensions and features, you can now use those as a guide to buying the right pool filter. First, the pool filter you need highly **depends on the pool’s size**.

All of the pool filters available on the market now have a ‘**gallon per minute’** design.

This is also true with most pool pumps to have a better idea of which pool filter to choose.

Once you have the measurements, you will be able to choose the pool filter easily.

For example, if you have a round pool approximately 7 meters in length, there are many filters.

That size of swimming pool usually contains around 13,500 gallons of water.

Hayward’s pool filter fits this as it can turnover 18,000 gallons of water in just ten hours.

Hayward is only one of the many brands that provide **high-quality filters**, so you can choose from any of the Hayward filters. Just make sure that the filter you choose has enough power to circulate the water.

There are also weaker pool pump filters like Intex for above-ground pools instead of your concrete swimming pool. If you have an above-ground pool, make sure to check out Intex pool pumps and filters.

Using the calculations that you made earlier, it is easy to choose the right size of pool filter. Just find the pool filter that is powerful enough to circulate the water at least once in 10 hours.

**Water Resistance**

You also need to consider the water-resistance applied to the pool filter as it will affect your filter’s turnover rate. Several types of pool filters offer different speeds.

For a pool filter that runs the water faster, the **resistance** will be greater than a pool filter with a slower water flow rate. That is why it is important to get a strong pool filter for your pool.

The basic standard is to get a pool filter that can circulate your pool’s water at least once in 10 hours. For the resistance issue, it is best to get a pool filter with two different speeds and power.

The slower flow rate on a **2-speed pool filter **gives you more flow. It reduces the resistance inside, which means that it does not use too much power to circulate the water.

However, you need to find the right balance between the high and low power of these kinds of pool filters as not all of them can attain the flow requirement when you set them to low.

**Tips On Getting The Right Pool Pump**

While we have a guide above that details all the processes you need to do to get the right pool filter size for your swimming pool; you can also follow some simple tips.

Here, we have a few of them to keep in mind to make sure that you get the best pool filter. So read on to know how you can improve the flow of water in your swimming pool.

**Bigger Is Better**

If you have calculated all the needed measurements for the pool filter, you will see the volume and the flow rate of your swimming pool. Based on those, you can choose the best pool filter.

Once you know how many **gallons of water** your pool can circulate, you can either get a pool filter that matches the needed flow rate, or you can get a slightly oversized filter for that.

It is best to get an oversized filter as it is meant for larger pools. Do not go too far out of the calculations as it might be too powerful that it degrades the other parts of the pool pump.

Again, around **2-5 thousand gallons **of water for the extra flow rate will be enough for the pool. Beyond that, there might be too much pressure on both the filter and the pipes in the pool.

**What To Do With Too Much Pressure?**

If the pool filter’s flow rate is too much for your swimming pool, you can either buy a new and weaker pool filter or make your pool plumbing system larger, especially the pipes.

You need to **increase the size **of the pipes around your pool, which can be expensive. You can also make some parts of the pipes larger and not change the entire plumbing system.

The operational system of the pool filter will have reduced pressure on it. This will help the pool filter function properly and help it prevent damages from happening.

**Commercial Pools**

If your swimming pool is meant for commercial use or for many swimmers regularly, you will need to get a very powerful pool filter to circulate the water properly.

There are **maximum and minimum flow rates** for every pool filter. Go too low or too high, and the cartridge filter will not operate properly, so make sure that you get the right filter for water volume.

Commercial pools need a more powerful filter to make sure that the water is always clean. If that is the case, then you need to circulate the water** at least four times** in one day.

**Conclusion**

To keep your swimming pool clean with pool cleaners and pool skimmers and have proper pool maintenance for the pool filter simultaneously, you need to run the pool filter at least once a day. This will help the swimming pool become cleaner.

You need to do not many things to make sure you get the right pool filter size, but you need to be precise to prevent damages from happening to the pool and the cartridge filter itself.

By following the guide above, you will get the best pool filter for your swimming pool. Make sure you get the right measurements and calculations to get the best filter.

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