Pool equipment – pumps, filters, automation


The pump is essentially the heart of the swimming pool’s circulation system. Your pool’s circulation system comprises the elements of your pool that take water from the pool, filters it, sanitises it, and returns the water back to the pool. If your pump is not running, the water from your pool is not being properly circulated or filtered.

Single speed

These pumps have been most common in the past as they are basically modelled to the size of the pool at a single speed to ensure the water in your pool is adequately turned over (circulated) on a daily basis.

Variable speed

Variable Speed Pumps are becoming more common with advantages of running at different speeds but in particular a very low speed but for longer. It is claimed to then save money on electricity costs. Variable speed pumps also have the advantage of being quieter during running and suitable for solar power. It is still critical that at a low speed there is adequate circulation in the pool and water turnover.


Media filters

Generally the most popular option, these units force pool water through a tank filled with finely graded sand or glass media. As it passes through, the impurities attach themselves to the fine sand or glass. The larger particles are trapped at the surface of the sand bed and the finest particles are collected deep inside the bed where the grains are more tightly packed.

Over time, the accumulated impurities will restrict the flow through the filter and the pressure gauge will indicate backwashing is required. This process can be controlled by the filter’s multiport valve. Once set to ‘backwash’, this valve will reverse the water flow and send the unwanted particles down the ‘waste’ line.

After a minute or so, the water should be clear again. Usually, a sight glass will allow you to monitor the process. Some filters even allow for automatic backwashing and this ensures the filter is always at peak efficiency, even if it has been left unattended for a prolonged period.

The NKD-R Freshwater System actually has a built, step-by-step process to take you through the process of backwashing your media filter.

Cartridge filters

As the name implies, these filters use a man-made cartridge as the filter medium and are becoming popular again due to their efficiency to filter water. Folded into the tank like a concertina, the filter material has a surprisingly large surface area. The principle does not involve a backwash line so they don’t need a connection to the sewer or waste line. This makes them ideal for spas and areas where disposal of waste is an issue.

Cartridge filters can be installed before the pump, and if necessary inside an oversized skimmer box when space is restricted. Cleaning is simply a matter of removing the cartridge and hosing it off, although having a second cartridge to use while the clogged unit is soaking overnight in a cartridge cleaning solution is recommended.

Pool heating


Solar is a relatively simple concept dating back centuries. A collector on the roof of the house made of either EPDM Rubber or a PVC/TPR material is used to collect heat from the sun. The collector can be a hollow panel, strips or tubing. Their simplicity means they have a low operating cost (typically a dedicated pump to drive water recirculation), are long life and are the most environmentally friendly option. Sizing, position (aspect to the north) and exposure/location will have a great effect on the efficiency and heat gain the system will deliver to your pool. In optimum situations, solar heating can extend your comfortable swimming season up to 3 or 5 months.


In most domestic situations gas is the quickest way to heat your pool and is also common in commercial situations as it’s relatively inexpensive to run in comparison to electricity. The availability of natural gas and LPG has made gas heating a popular choice for swimming pool heating. You need to ensure you have a correct size heater to the size of your pool, just like warming the house at home. i.e. maximum desired temperature. If you only use your pool on occasion it can be the most efficient as a larger heater will raise temperature rapidly, only when you need it.

Heat pump

Heat pumps are highly energy-efficient and operate along with the same principles as a refrigerator, except in reverse. Because they ‘extract’ heat from the air it only takes one-fifth of the energy to run them as they are producing. I.e. A heat pump may produce 6 to 10kW of Heat energy for every 2kW it consumes. Not ideal for use with salt water or mineral pool as the salt can deteriorate the components. Most domestic setups will operate on single-phase power.

Pool automation

Increasingly popular are options to automate your swimming pool or control via an App on your phone. Apps can help you make set-points or control your equipment from the comfort of your lounge room chair, but there are still times you are going to need to be involved with your swimming pool other than just relaxation.

There are controllers on the market that can measure your chlorine and pH demands and dose chemicals as required taking some of the manual work out of water testing. It is important to note that these also require calibration and if the sensors are not reading the water correctly the chemistry of your pool may not be correct.

Generally, peristaltic pumps are used for dosing. They employ a squeeze tube system and the tube will eventually need to be replaced. With higher pressures, there can be issues with the injection point back-pressure. Diaphragm pumps are more expensive but can inject into higher-pressure applications and are claimed to be more reliable, especially with automatic bleed valves fitted.

Solenoid valves are very reliable and low maintenance, with only two moving parts. They require suction to operate. Installation is before the filter, on the suction side of the circulating pump, or after using a venture system.

Dosing systems cannot refill themselves full of chemicals so once again, there is still manual intervention required when maintaining your pool water. Our suggestion is that if you can spend 10 minutes a fortnight during summer (5 minutes a week) testing your pool water, you will completely understand how simple it is to maintain your pool with the right quality equipment.

If you have any other questions, please give us a call on 1800 625 331 or use our CONTACT US page.