Why a pool turns green in Cyprus
Algae need warm water and too little chlorine. A Cyprus summer supplies the warm water. In a heatwave, when the afternoon gets to 40 °C, the sun burns chlorine off faster than usual, and a pool that looked fine at the weekend can be cloudy green a few days later.
The dust that blows over from the Sahara is the other local cause. One Paphos pool company writes that a dusty day can strip the chlorine out of a pool in under 12 hours. The fine sand settles on the floor and the filter clogs sooner.
Pool turned green after rain? Rain waters down the chlorine and washes dust, leaves and garden soil off the deck into the water. If it rains on a dusty day, the dust comes down with it.
Chlorine lock is the slow one. Stabilised chlorine tablets leave cyanuric acid in the water, and over a season or two it builds up until the chlorine stops working, even when the test strip says there is chlorine in the pool. The owner adds more tablets and the pool goes green anyway. The usual way out is to replace part of the water, and the company decides that after it has tested the pool.
The rest is the pump. A timer that reset after a power cut, a pump turned off in August to save on electricity, a holiday let in Protaras between two bookings with nobody looking at the skimmer. Still water with no fresh chlorine goes green fast in summer. The heaviest case is a villa in Peyia that sat empty all winter with the pump off: by spring the water is dark, the floor is under a layer of leaves and the filter needs a proper clean.
A tint, green or dark: what each state takes
The request form asks which of three states your pool is in, because the work is different for each. The prices in the last column are from the same Paphos price list.
A tint: cloudy or greenish water, you can still see the floor
What it usually means: Chlorine dropped for a few days and algae have just started
What it usually takes: Shock treatment, brushing, filter clean. From €200
Green: clearly green, the floor is hard to make out
What it usually means: A full algae bloom
What it usually takes: Shock, brushing walls and floor, several filter cleans. From €450
Dark: you can't see the floor, often leaves and silt underneath
What it usually means: Weeks without circulation, often a pool switched off for the winter
What it usually takes: Leaves and silt out first, then treatment and many filter cleans. About €550
| What you see | What it usually means | What it usually takes |
|---|---|---|
| A tint: cloudy or greenish water, you can still see the floor | Chlorine dropped for a few days and algae have just started | Shock treatment, brushing, filter clean. From €200 |
| Green: clearly green, the floor is hard to make out | A full algae bloom | Shock, brushing walls and floor, several filter cleans. From €450 |
| Dark: you can't see the floor, often leaves and silt underneath | Weeks without circulation, often a pool switched off for the winter | Leaves and silt out first, then treatment and many filter cleans. About €550 |
Another company that works across the island gives a fixed price after an inspection and says the job usually takes two or three visits. The company that takes your request looks at the pool first and then tells you which case you are in.
Water in any of these three states is not for swimming. Keep children and dogs out until the company says the pool is clear.
What to do before the pool company comes
A few things help, and none of them involve chemicals.
- Turn the pump on and leave it running. Moving the water through the filter is the first step of every clean-up, and it stops things getting worse while you wait.
- Empty the skimmer baskets and the pump basket, and scoop out leaves and anything floating.
- If the filter has a pressure gauge, write down the reading and tell the company.
- Don't drain the pool in summer. An empty pool in the Cyprus sun is hard on tiles and liners, and the company will usually treat the water instead of throwing it away.
- Don't pour one shop product on top of another. Some pool chemicals react with each other, and the company needs to know what has already gone in.
- Take two photos, one from the side and one looking down at the floor. They help you pick the right state on the form and show the company what to expect.
How many visits a green pool takes and what it costs
Usually two or three. The first visit does the heavy work: leaves out, walls and floor brushed, the shock added, the filter cleaned. The next ones test the water, clean the filter again and keep the chlorine up until the water stays clear on its own.
- Cloudy or a light tint, shock treatment
- €200 and up
- Green, full algae bloom
- €450 and up
- Pool switched off all winter
- about €550
- Visits
- usually 2–3 until it is clear
What pool companies on the island charge, from their own price lists, property guides and listings (October 2026); VAT is not always included. The company that takes your request names the exact price once it has seen the pool.
For comparison, the Paphos company's April 2026 list gives €200 and up for a shock treatment, €450 and up for a full algae bloom and around €550 to bring back a pool that was switched off for the winter. The final price comes after the company has seen the pool: its size, how dark the water is and how much is lying on the floor.
How to stop it turning green again
A pool that went green once will go green again for the same reason unless something changes. If the pump was the cause, fix the timer or the electrics. If it was chlorine lock, have the stabiliser level tested and ask the company whether to move away from tablets.
For most owners the change is regular visits. On the island the usual schedule is twice a week from May to October and once a week from November to April. Someone who comes that often tests the water, empties the skimmers after a dusty day and sees the chlorine dropping before the water turns. The same Paphos company charges €115–145 a month for an 8×4 m pool in summer, with chemicals €25–40 a month on top.
If you only use the house in summer, ask about winter care as well. A pump left off from November to April is the €550 case in the table above.