Can a Pool Pump be too Big?

There is a slew of concerns pool owners go through to ensure their pool is functioning at peak performance. Finding the appropriate size for your pool pump is something that people rarely think of, but it is critical to its performance. When it comes to your pool pump, can it be too big? 

If you choose a pool pump that has a flow rate that is higher than the filter it can strain the filter itself and cause issues for the pool pump. If the pool pump’s flow rate is too low, it can have the same effect. Pair both units so their plumbing pieces match to ensure the best performance. 

The last thing any pool owner needs to worry about is how well their pool pump is functioning. The pool pump is essentially the lifeline of the pool and if it is not matched well with your filter, bad news could be in your future. Continue reading to see what the importance is behind the size of your pool pump, the amount of power that it is using, and how this affects the efficiency of your pump as well as your filter. 

Why Does the Pool Pump Size Matter? 

There are so many different pieces of pool ownership that come together in one cohesive unit to form an enjoyable pool experience. These things can be small, like finding the perfect raft for sunbathing or getting the best cooler to sit poolside while you lounge the day away. Or, these pieces can be big things like maintaining the proper chemical balance within your pool or even bigger, ensuring that the pump size is appropriate for your filter. 

Ultimately, the pool pump size matters as it ensures a proper flow rate to avoid straining the filter. Additionally, this helps to balance the chemicals in your pool to create a clean environment (free of harmful bacteria) in which you plan to swim.

When it comes to the size of your filter, there is no such thing as having one that is too big. Really, it can even be beneficial to have a pump that is larger than what your pool size requires because it puts less strain on the filter and leaves more room for debris to make its way through. With this being the case, you may think that the same rules that are applied to the filter can be applied to your pool pump size, but this could not be further from the truth. 

Pool pumps work as the heart of your pool. The pool pump is what creates the flow of water that helps to pull all the chemicals through the filter and back out into your pool. This helps to create a chemical balance that is evenly distributed throughout the pool. This simple task is what keeps your pool clean and free of any harmful bacteria that can easily bloom and build up if the circulation is not properly flowing. 

With a pool pump, the proper flow rate is the most important aspect of its own function, but also with the compatibility of your filter. Ideally, you want to match a pump’s inlet and outlet with the same size of the filter. If the pump inlet/outlet is 1-½” the filter’s inlet/outlet should be as well. If your pool pump is too small for the filter inlet/outlet size, it can put a huge strain on the pump as it will try to overwork in order to match the flow rate of the filter. 

However, if the pump is too big, it will begin to strain the filter, rather than the pump. The pump will pull larger amounts of water than the filter is able to effectively filter through. The pull of water will then cause insufficient filtering and too fast of a flow rate throughout the filter. 

This high flow rate can also cause damage to the filter. If water is being pushed through the filter at a rate that is too high for its design, it can cause the filter to work insufficiently when it comes to actual filtration, but it can also wear on the medium of the filter in a way that can either create a need for a medium change too quickly, or can wear out the system within the filter completely resulting in a total filter replacement. Ultimately, this is a replacement that is not cheap. 

Why Does Pool Pump Power Consumption Matter? 

Beyond the size of your pool pump, you also have to consider the amount of power that your pool pump will be using. This area of pool pumps is much less discussed, but it is just as important as the pool pump size itself. This is not a cookie-cutter situation though as the power that your pool pump consumes includes the size of the pump, the piping on it, and the quality of your filter. Many components play a part in its power consumption, making this topic all the more important.

Pool pump power consumption matters in that it allows the appropriate rate of filtration to prove effective while not putting too much strain on the other components of your pool. The right flow rate will help your pool pump, filter, and pool to function effectively and cohesively.

Many pool owners are under the impression that if you purchase a pool pump with more horsepower, you will in turn have a pool pump that is more efficient due to its ability to work quickly at a higher rate of speed. However, horsepower is misleading in this area because the horsepower rating of pool pumps only implies how much it is going to cost you to run that pump per hour of use. 

If you have a pool pump that has a 2 horsepower motor that is working with a 1.55” filter in a 15,000-gallon pool, your pool pump is going to be working at an entirely too high rate for the size of the filter and for the size of the pool. You may be inclined to believe that the higher horsepower means more effective filtration due to its speed and ability to pump through more water at a higher rate, however, it is actually quite the opposite. 

A higher horsepower tells you absolutely nothing when it comes to your pool pump’s ability to filter water. Flow rate is what determines this aspect and it is what should be adhered to when it comes to filtration. 

However, these two are tied together in a very important way. To achieve a good flow rate, you want a pool pump with the lowest possible horsepower that will also meet the flow rate requirements that are needed from your filter. 

Why is this? First, a lower horsepower is going to save you energy costs when it comes to running your pool pump. Second, and most importantly, a lower horsepower also means that the flow rate will be appropriate for your filter and thus, your water will be filtered at the correct rate within a 24-hour period. If you have a 15,000-gallon pool, you need to filter 45,000 gallons every 24 hours. Ideally, those 15,000 gallons should be filtered entirely 3 times a day. 

This means that your pump does not have to run continually, but only that specified three times to ensure that the water has been cleaned and that the chemicals have been properly dispersed. If you were to run your filter constantly, your pump would be overworked, your water would be unnecessarily filtered through, and your energy costs would be through the roof. 

Many times, pool owners who have purchased a pool pump that has a higher horsepower will run the pump less in order to lower the cost of operation. Remember, higher horsepower means a bigger need for energy, which means more cost to you. This can cause problems within your pool though as your water does not receive the proper filtration that it needs in order to maintain a healthy environment with properly distributed chemicals and sanitation. 

When it comes to the power of your pool pump, the most essential thing to remember is that more horsepower does not mean more efficient pumping. Match the flow rate of your pump to your filter, but also be sure to purchase a pump with a lower horsepower to ensure that less energy is burned, but more effective filtration is achieved. More horsepower may be the best thing for your muscle car, but it has quite the opposite effect on your pool pump.

Jed Arnold

Jed spent every year from the ages of 15 - 22 as a Lifeguard (Red Cross) and ages of 17 - 22 as a Certified Pool Operator (CPO). Between working for over a dozen facilities and owning a pool, he carries over a decade of pool experience.

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