Keeping your pool filter clean is one of the most practical things you can do to maintain water quality. In Cyprus, filters work harder than in most European countries. The combination of intense UV, high summer temperatures, calcareous dust, and genuinely hard water puts a constant load on filtration systems. If you skip backwashing for too long, the filter media becomes compacted, flow rate drops, and your pump starts working against rising back-pressure. The result is cloudy water and a shorter lifespan for your equipment.
What Type of Filter Do You Have?
Before you touch anything, identify your filter type. The backwashing process differs significantly between them.
Sand filters are the most common in Cyprus residential pools. They use a bed of silica sand (or sometimes crushed glass media) to trap particles. These require backwashing every one to two weeks during summer, sometimes more often after a dust event.
Cartridge filters do not backwash in the traditional sense. You remove the cartridge element and rinse or soak it. If you have a cartridge filter, skip to the cleaning section below.
DE (diatomaceous earth) filters are less common in residential settings here, but they are used. They require backwashing followed by recharging with fresh DE powder.
How to Backwash a Sand Filter: Step by Step
1. Turn off the pump
Always start with the pump off. Switching the multiport valve while the pump is running can tear the internal spider gasket, which means a repair job and parts that can be slow to source locally.
2. Set the valve to BACKWASH
The multiport valve on top of or beside the filter has several positions. Rotate to BACKWASH. You should feel it click into place.
3. Attach or check the waste line
Make sure the backwash hose is directed somewhere appropriate. In Limassol and Paphos, many properties discharge to a drain or a designated waste point. Do not backwash directly onto planted areas repeatedly — the high chlorine content and salt (if you use a saltwater system) will damage soil and plants over time.
4. Run the pump for two to three minutes
Switch the pump back on and watch the sight glass, if your system has one. The water will initially run cloudy and brown, carrying out the accumulated debris, algae fragments, and fine particles. Run it until the sight glass shows clear water. In Cyprus in summer, after a Saharan dust event, this can take longer than you expect — four or five minutes is not unusual.
5. Switch to RINSE
Turn the pump off, switch the valve to RINSE, and run for around thirty seconds. This reseats the sand bed and flushes any remaining dirty water out of the laterals before it returns to the pool. Skip this step and you risk pushing a slug of dirty water back into the pool when you return to the FILTER position.
6. Return to FILTER
Pump off, valve to FILTER, pump back on. Check the pressure gauge. You should see a drop compared to the pre-backwash reading — typically back toward your baseline clean operating pressure.
Cleaning a Cartridge Filter
Remove the cartridge element and inspect it. In Cyprus, cartridge filters accumulate calcium scale relatively quickly because of the hard water. A simple hose rinse is often not enough.
For routine cleaning, use a garden hose with a spray nozzle and work from top to bottom between each pleat. Do not use a pressure washer directly on the pleats — the high pressure degrades the polyester fabric over time.
For a deeper clean, which you should do every four to six weeks in summer, soak the cartridge overnight in a filter cleaning solution. Alternatively, a diluted muriatic acid soak (roughly one part acid to twenty parts water) will dissolve calcium deposits. Handle acid carefully, work outdoors, and wear gloves and eye protection. Rinse the cartridge thoroughly before reinstalling.
A cartridge has a finite lifespan. If the pleats are torn, the end caps are cracked, or the fabric is permanently discoloured and stiff despite cleaning, replace it. Running a compromised cartridge defeats the purpose of having filtration at all.
How Often Should You Backwash in Cyprus?
During the swimming season, which in Cyprus effectively runs from April through October, backwash your sand filter every seven to fourteen days as a baseline. Adjust based on bather load and conditions. After a heavy dust storm, backwash the following day regardless of your schedule. If your pressure gauge reads eight to ten psi above your clean baseline, that is your cue to backwash immediately.
Owners of holiday villas and rental properties should build a backwash into every pool visit. Guest pools accumulate sunscreen, body oils, and cosmetics at a much higher rate than private residential pools, and the filter reflects that load quickly.
One thing worth noting: backwashing does not replace the eventual need to change your sand. Sand media in Cyprus pools should typically be replaced every three to five years. Channelling, calcium cementation, and oiling of the sand bed all reduce filtration efficiency in ways that backwashing cannot fix.
When to Call a Professional
If you are backwashing regularly and still seeing cloudy water, or if your pressure gauge does not return to baseline after a backwash, the problem is likely elsewhere — a worn multiport valve, a cracked lateral inside the filter tank, or a water chemistry issue that is overwhelming the system. These are worth having assessed properly rather than guessing at.
Pool Cleaning Cyprus provides filter servicing, sand changes, and full maintenance contracts across Limassol, Paphos, Nicosia, and Larnaca. If your filter is not performing as it should, get in touch by phone or email and we will take a look.