Choosing a Pool Pump

Pool pumps are normally purchased by “horsepower” (Hp) or Watts. Not surprisingly, the higher the horse power, the greater volume of water it can move (i.e., the higher the performance).

Performance is normally measured in “litres per minute” (L/min).
It’s worth noting that two pumps of the same horsepower (or watts) may actually pump different volume per minute – That’s you should always look at the specific flow rate of the model you will consider.

Choose A Pump That Is Powerful Enough – But Not Too Powerful !
This is an important point – many pool owners who are unhappy with their pump’s performance consider purchasing a more powerful pump.

	Firstly, this can cause serious problems – your filter and plumbing can only handle up to a certain amount of flow rate. Exceeding this will cause serious and expensive problems.
	Secondly, performance issues with pumps are usually related to issues such as air being sucked into the pump. Please refer to our article on this topic, >> Pool Pump Troubleshooting

Choosing The Right Size – Check Your Filter’s Maximum Flow Rate
The most important issue is that you don’t approach your filter’s maximum flow rate. Placing a powerful 1.5hp pump on an average sized 24 inch diameter sand filter may cause many problems.
A general guide - The diagram below summarizes the most popular combinations of pump and filter: In most cases, when replacing a pump it’s wise to stay with a similar rating to what you already have (unless you have a specific need to change).

BTW - Turning Over Your Pool Volume In A Reasonable Time
A further consideration for some pool owner’s is how long the pump takes to turn-over the whole pool volume (i.e. its “turnover time”). We recommend that you fully turnover the pool volume once each day. The table below will give you an idea how long various pump take to turnover typical pool volumes:

Generally, it's more than adequate if your pump can turnover your pool volume in around 6 hours or less. Frankly, most filtration systems need to run this long simply to allow salt chlorinators to properly sanitise the pool.

Pump Size > 0.75hp 1.00 hp 1.25hp 1.5hp Flow Rate > 150 L/min 210 L/min 275 L/min 320 L/min 40,000 litres 4.4 hrs 3.2 hrs 2.4 hrs 2.1 hrs 50,000 litres 5.6 hrs 4.0 hrs 3.0 hrs 2.6 hrs 60,000 litres 6.7 hrs 4.8 hrs 3.6 hrs 3.1 hrs 70,000 litres 7.8 hrs 5.6 hrs 4.2 hrs 3.6 hrs

Electrical Costs - While it can be handy to turnover your pool volume quickly, keep in mind you probably won’t save on electricity costs. While you pump may run for less time, it is likely using more energy per hour.