This is not based on Horse Power it is based on "Flow Rate", which is expressed in Gallons Per Minute (GPM).
Horse Power is NOT RELEVANT when buying a pump, in fact the number one problem in the pool industry is over sized pumps.
Buying a pump based on horsepower alone does nothing but waste electricity.
There are two laws making their way from state to state right now called title 20 and title 24.
These laws effectively outlaw energy wasting pool pumps.
Once you know the desired turnover rate, you can determine your desired flow rate.
Use the following equation to determine the desired flow rate:
Pool Size - number of gallons of water in the pool
Turnover Time - time to move entire capacity of pool through filter
Flow Rate - desired flow rate in gallons per minute
|35,000||divided by||8 hours||divided by||60||equals||73 GPM|
|35,000||divided by||10 hours||divided by||60||equals||58 GPM|
|24,000||divided by||8 hours||divided by||60||equals||50 GPM|
|24,000||divided by||10 hours||divided by||60||equals||40 GPM|
|18,000||divided by||8 hours||divided by||60||equals||38 GPM|
|18,000||divided by||10 hours||divided by||60||equals||30 GPM|
If you have a 25,000 gallon pool and want a turnover rate of 8 hours, then you will need a pump with a flow rate of 52 gallons per minute.
If you have a 35,000 gallon pool and want a turnover rate of 10 hours, you will need a pump with a flow rate of 56 gallons per minute.
For this situation, we will use a 24,000 gallon pool with a turnover time of 8 hours, giving us a MINIMUM FLOW RATE of 50 gallons/minute.
Flow rates are published by pump manufacturers. Match the rate from the chart above with the rate from the manufacturer then buy that size pump. Don't be fooled by horsepower numbers. They are usually inaccurate and misleading.
If it is in your budget, purchase a multi-speed pump to save up to 75% in energy costs.