A pool pump is considered the heart of the swimming pool, and it’s not without reason. The right pool pump will promote adequate pool circulation and ensure that your swimming pool is properly cleaned. It uses an electric motor to create suction and pull water from the pool through its filtration system and into the swimming pool.
This helps clean and filter the pool water, eliminating dirty and stagnant water that may be unsafe for swimming. However, shopping for the right pool pump can be overwhelming, especially if you are a first-time pool owner. This involves some basic calculations to get the right pump size for your needs or your existing system.
Compiled below is a comprehensive step-by-step guide for selecting the ideal pool pump for your needs.
1. Measure Your Pool
Contents
The first thing before selecting a pool pump is measuring the volume of your pool.
Volume = Length (ft.) x Width (ft.) x Depth (ft.)
To take the measurements, you will need a tape measure. If the pool has different depths, it is advisable to sue the average depth, which is given by adding the shallow depth and the deep depth and dividing by 2. Once you have the volume, you need to convert it into gallons.
1 cubic foot is equal to 7.48 gallons (approximately 7.5 gallons)
For Example: Suppose your pool measures 35ft long, 20ft wide, and 6ft deep; the volume will be:
V= 35ft x 20ft x 6ft= 4,200ft
To get in gallons= 4,200x 7.5= 31,500 gallons
If you find this hard to calculate, you can use a pool calculator like this to help you.
2. The Required Water Flow Rate
Now that you have the pool’s volume, it is time to work out the pump flow rate. In simple terms, this is the speed at which the pump circulates water through the pool’s circulation system for a given time. Usually, the water flow rate will depend on the pool size water features available such as waterfalls and fountains.
It is also tied to the turnover rate, which is the time to move the total pool capacity through the system. While the turnover time varies from one region to another, the standard turnover time commonly used is 8 hours.
Step 1: To get the required water flow rate, you must divide the volume of the pool in gallons by 8 hours. For instance, if the pool capacity is 31 500 gallons, then the required water flow rate will be:
=31, 500/8hour=3,937.5 gallons per hour (Approximately 3,938 Gallons per hour)
Step 2: Since most pumps are rated in gallons per minute, we need to divide the figure by 60 minutes.
=3,938 gallons /60 minutes= 65.6/m (Approximately 66 Gallons per minute)
Therefore, for a 30,000-gallon pool, a pool pump with a flow rate of about 66 GPM would be ideal.
Generally, swimming pools with 10,000 to 15,000-gallon capacity may need a pump with a flow rate of 20 and 35 GPM, those with 20,000 to 40,000-gallon capacity will do with a flow rate of between 40 GPM to 80 GPM, while pools with 40,000-gallon capacity and above may require a flow rate of between 83 GPM and 120 GPM.
If you already have an existing pool pump, consider installing a flow meter to measure the current water flow rate in gallons per minute. If the flow rate is high enough, you can simply install a pool pump of a similar size.
3. Calculate the Total Dynamic Head (TDH)
This is the total equivalent height that fluid will be pumped while considering the friction loss and resistance working against the pump. Also known as the feet of head number, TDH can be impacted by the rise in elevation, pipe’s length, and addition of 90-degree or 45-degree turns.
Basically, the higher the friction, the harder your pump will work to get water through the pipe. You will need to use a larger pipe or a higher HP in this instance. Besides, the pump flow rate will depend on the feet of the head. Therefore, you must calculate the system’s feet of the head before installing a new pump or even replacing the filter.
In general, you will need a pump with an average total dynamic head of 50 to 60 if you own an above-ground pool. However, if you have an in-ground pool, a pump with an average total dynamic head of 20 to 30 would suffice.
4. Match to Your Filter
A common mistake that you may want to avoid is mismatching your pool pump with your pool filter. This can result in poor water circulation and inefficient filtration. Ideally, you need to ensure that the pump you choose pairs well with your filter of optimal performance. Before you purchase, determine the inlet/outlet pipe size of your filter and get a pump with the exact pipe size.
5. Type of Pump
With all these facts in place, you need to determine the correct type of pool for your needs. Of course, the type of pool will depend on the output you need and your pool type.
- Single-Speed Pump-This is an affordable pool pump that runs at one speed. It can operate at a speed of about 35000RPM and is not as energy efficient as the other pumps.
- Multiple-Speed Pump– This pump has two-speed settings, allowing you to operate at a low speed OF about 1750 RPM and high speed of about 3500 RPM. Although expensive, it is more energy-efficient than the single-speed pump.
- Variable Speed Pump– This pump has a wide range of speed pumps, ranging from 450 RPM to 3500 RP, to fit every task. It is quieter and can help you save up to 70% on energy costs than the single-speed pump.
Conclusion
That is basically everything you need to know when figuring out your pool’s pump needs. When shopping for a swimming pool pump, you want to determine how much it will cost to own and operate one.
Your pump should serve you for an extended time as long as you choose the right pump for your pool water volume and your filter. You may also want to consider getting a variable speed pump to get value for your money in the long run.
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