If you’re looking to get your pool sparkling clean, a sand filter is a must-have piece of equipment. As the name suggests, a pool sand filter uses sand to filter pool water. The water passes through a chamber filled with sand, trapping particles, debris, and other contaminants. The purified water flows out of the sand filter and back into the pool.

Having a pool sand filter allows you and your family to relax in clean, clear water throughout the hot Australian months.

But before taking the plunge with buying a sand filter, ask yourself, “what size sand filter do I need for my above-ground pool?” Answering that question is important as choosing the right size filter will affect how well it cleans the pool and its overall efficiency.

This guide will answer that question and show you what you need to know to correctly size your above-ground pool filter.

What Do I Need To Know to Size a Pool Filter?

When sizing a sand filter for your pool, there are several factors you have to consider. The most important ones include

  1. The size and volume of your pool
  2. The required turnover rate of your pump
  3. The required pump flow rate

These three factors are vital in helping you determine the size of sand filter to purchase for your above-ground pool. It’s important to know these measurements before choosing a filter so you don’t end up with one that is too small or too large for your pool and pump.

The Size and Volume of the Pool

When determining the size of the filter you need, one of the first factors to consider is the size and volume of your pool. The sizing will determine how much water needs to be filtered, affecting the size and type of filter you purchase.

To work out the volume of your pool, you will need to measure the length, width, and depth, then use this formula.

V = L x W x D

Where V is the volume, L is the length, W is the width, and D is the depth of your pool. For example, if you have an above-ground pool that is 7m long, 5m wide and 1.2m deep, the volume can be worked out as follows.

V = 7 x 5 x 1.2 = 42,000 litres

Once you know the total volume of your pool, you need to factor in how much water needs to be filtered and how often. You can determine these figures by the pump flow rate and the turnover rate of your pool, which we’ll discuss next.

The Required Turnover Rate

The turnover rate of your pump refers to how often the entire pool’s water needs to be filtered. Turnover rate is essential for keeping the water in your pool clean and clear, so you must know this measurement before purchasing a sand filter. The industry average turnover time is Between Six and Eight hours for outdoor pools in Summer and Four hours in Winter

So if your pool has a volume of 42,000 litres, the total amount of water that needs filtering in Eight hours is 42,000 litres. You can use the following formula to work this out in litres per minute.

Litres per min = Pool volume ÷ Total turnover time

In this example, it would be 42,000 litres ÷ 480 minutes (8 hours) = 87.5 litres per minute. This figure is your pool’s turnover rate required for your filter. But there’s one more aspect you need to take into consideration before going out and buying your sand filter.

The Required Pump Flow Rate

The pump flow rate measures how much water is pushed through the filter. This amount must be greater than the turnover rate, as it needs to compensate for any backwash or losses due to system friction. You must factor in any additional losses to determine the total pump flow rate.

Adding a minimum of 20% extra flow rate for an above-ground pool for these losses is recommended. If your turnover rate was 87.5 litres per minute, your pump flow rate should be at least 105 litres per minute.

Now that you know all the measurements needed to size a sand filter for your above-ground pool, it’s time to put this information into practice.

How To Calculate the Size of the Sand Filter You Need

If you type into Google “what size sand filter do I need for my above-ground pool?”, you will find some great online calculators you can use to figure out the answer. All you need to do is enter the measurements of your pool, such as volume and pump flow rate, and the calculator will calculate the size of the filter you need.

If you prefer to calculate the size of the sand filter the old-fashioned way, use this formula.

Volume ÷ Turnover Time
= 42,000 L ÷ (8 hrs x 60 mins/hr)
42,000 L ÷ 480 mins
= 87.5 LPM
Then add an extra 20% capacity safety margin = 87.5 LPM x 1.2 = 105 LPM

Where volume is the total volume of your pool in litres, turnover time is the total time it takes to filter the entire pool, and additional losses are a minimum of 20%. So, you should choose a sand filter with a max flow rate equal to or more than 105 LPM.

Keep in mind that this is only a rough guide. Other factors, such as the type of pool you have and its water quality, can also affect the filter size you need. It’s important to double-check all measurements before purchasing a sand filter for your pool. One size higher is aways recommend.

If you need any advice, our team at Hy-Clor can take the hassle out of finding the right sand filter. We will provide all the information you need to find the perfect size pool filter for your pool.

Examples of The Right Filter Size for The Pool

Let’s now put the above formulas into a real-life scenario. Here is an example of working out the required sand filter size for an above-ground pool using what you have learned so far.

Suppose your pool has a volume of 61,000 litres and a turnover time of 6 hours. These measurements mean your pump flow rate is 169.4 litres per minute. Adding on the 20% for additional losses means you would need to buy a sand filter with a max flow rate equal to or more than 203.3 LPM.

In this situation, the Hy-Clor 24-inch sand filter is an excellent choice for this size pool. Our Hy-Clor 24-inch pool filters are

  • Easy to install.
  • Easy to operate with multi-port operating valves.
  • Suitable for sand and most media types and ideal for ZeoClor.
  • Suitable for small to large-sized residential in-ground and above-ground pools.
  • Ideal for chlorine or saltwater pools.
  • Made of chemical-resistant components and plastics.
  • Available with a full range of spare parts for easy replacement.

Choose The Right Size Filter for Your Pool

If you’re considering putting in an above-ground pool at your place, choosing the right filter size is essential to get right. Why? Because if you get it wrong, it could mean your pool water is not as clean and balanced as it should be.

Installing the wrong size filter can also cause excessive pressure on your pump and filter system. This pressure will not only lead to extra wear and tear but will also contribute to a larger power bill at the end of the quarter.

Using the tips and formulas above, you can determine the right sand filter size for your above-ground pool. Having trouble figuring out how to use the formulas? Please reach out to us here at Hy-Clor.

We are one of the largest swimming pool treatment and equipment suppliers in Australia and New Zealand. Our team of experts at Hy-Clor will help you find the perfect size sand filter for your above-ground pool.

Call us on 1800 625 123 or complete our online enquiry form. Alternatively, please call us on 1800 625 123 if you’re in Australia or (09) 973 2477 if you’re in New Zealand. You can also visit your local Bunnings for a complete range of HyClor products.