2020 FAQ: What Size Pump Do I Need For My Above Ground Pool?

A good pump is a necessity, especially when planning to build a new swimming pool. It is also quite useful when you want to replace the old one with something better. It’s important to choose the best one. To do this, you would have to watch out for two factors. First is the filter combination, second is the size of the pump

A good size or fit has to match the flow rate of the filter. Here, the focus is not so much on the brand, model, or exact type of pump. Instead, it is on the size. Therefore, the question to ask is, “What size pump do I need for my above ground pool?” Without the appropriate size, you would be straining the pump and filter beyond their capabilities thus increasing possibility of damages.

Calculate the Size of the Pool Pump

The first step is to calculate the size of the pump that your pool needs. In doing so, it would be great to mention that the size is not limited to the horsepower (HP) of the motor alone. Instead, size also delves into factors such as gallons per minute (GPM) of water flow. Typically, a good pump is capable of pumping all pool water through a filter in between 8-10 hours.

Anything beyond this and it is clear that your pump would be struggling. Based on this, you should go with the capacity for pumping 40GPM or 80GPM when dealing with a small and larger pool respectively. Bear in mind that these figures are nothing but generalities: hence, you should strive to calculate exactly what your pool needs.

To do that, you would have to:

  1. Calculate the number of gallons that your pool holds
  2. Calculate how many gallons you have to pump out of the pool per hour within 8 hours
  3. Divide the number of gallons in your pool by 8
  4. Divide the number you get in (c) by 60, since 60 minutes are in an hour

To understand this better, let’s be a bit more practical by assuming that your pool holds 24,000 gallons. Next, in dividing 24,000 by 8 we get 3,000. Because pumps are labeled on the number of gallons they are capable of moving per hour, the next step is to divide 3,000 by 60, which gives us 50 gallons per minute. Therefore, essentially you now know that a good pump for your pool is one rated 50GPM.

However, that is not all. Initially, we said the pump has to be capable of moving water in 8-10 hours. Based on this, you would be right to divide 24,000 by 10 too, which would give you 2,400. Upon dividing 2,400 by 60, you would get 40GPM. Consequently, any pump rated 40-50GPM would meet your needs effectively even without paying any attention to the HP.

In-Ground Pumps

The information above is for anyone who asks, “What size pump do I need for my above ground pool?” However, it is also worth stating that not every person has an above ground pool. For this reason, it is acceptable to talk about in-ground pumps. To do this, it would be prudent to consider the most important factors here.

Essentially, the most important one is the distance between the pool and the pump. In this regard, it is worth noting that GPM reduces the further the pump is from the pool. Apart from that, PVC turns and valves affect the pump’s GPM too. If you have fitted waterfalls, fountains, and spas, then you would need a pump with a much higher GPM and HP as well.

It is important to note that the GPM of the pool pump is in direct proportion to that of the pool’s filter. A rule of thumb is to keep the filter’s GPM higher than the pump’s. That way, you would be minimizing any likely strain on the pump’s motor. Additionally, you should not limit your options or factors on which to base your selection on high GPM and high HP alone.

As we have learned above, these two factors are critical. However, you cannot and should never ignore the pool’s maximum flow rate. This factor is dependent on the pipes fitted around the pool. Therefore, learn to keep a keen eye on the pipes, which you might have to consider replacing if they do not meet the following specifications:

  1. Maximum flow rate for a pipe with an intake line of 1.5” is 42GPM
  2. Maximum flow rate for a pipe with an intake line of 2” is 73GPM
  3. Maximum flow rate for a pipe with an intake line of 2.5” is 120GPM
  4. Maximum flow rate for a pipe with an intake line of 3” is 160GPM

Above Ground Pumps and Filters

Are you unhappy that your pool pump lacks the requisite horsepower? Do not panic over such an issue. That is because you have several options to implement and make the pump more efficient. Here, efficiency simply means getting the most GPM from the pump. One strategy revolves around increasing the size of the PVC pipe from 1.5” to 2”.

Such a simple strategy would improve your pump’s GPM substantially. That is not all, though! Other options include adding a pump timer, going for a pump that has a 2-speed motor, and investing in fresher variable speed pumps. With these measures in place, you would never have to scratch your head in question while asking, “What size pump do I need for my above ground pool?”

Our Final Thoughts On “What size pump do I need for my above ground pool?”

This article has sought to answer your question. Now you know the factors to consider before selecting any pump for your above ground pool. Remember to check the gallons per minute (GPM) rating on the pump always. It is the most important quality of the pump and helps you to determine the actual size that your pool needs. As shown above, it is more important than the pump’s horsepower (HP). Additionally, you should keep your eyes open for the pool’s maximum flow rate. Do not ignore the distance between the pump and the pool too, as this piece of information helps you to choose the best size too. Do not forget that it does not hurt to seek more information or ask for assistance where you feel confused to avoid wasting money buying the wrong pump.