10 Expert Swimming Pool Tips: A Summer Guide for Homeowners in the Algarve

By mid June the pool has become the busiest room of an Algarve house. It is also, quietly, the hardest working: at 30°C and above, under a sun that shows up around 300 days a year, water misbehaves faster here than anywhere else we work. These ten swimming pool tips are the ones we find ourselves repeating most often after 18 years in the region. Some will look familiar. The reasons behind them mostly will not.

Why do pools in the Algarve need special attention?

Because the local conditions are harder on water than most owners realise. Chlorine that would last a fortnight in Manchester is gone here in days. Through August the level drops a little every morning, whether or not anyone has swum. Then there is the dust. When the wind comes off the Sahara, a pool that was clear at breakfast can be hazy by evening, and the filter goes on paying for it for a week afterwards. Underneath all of it sits limestone, so the mains water arrives already carrying calcium. None of this is a crisis. It is a different climate, and it asks for a different routine.

Tip 1: Master your water chemistry

Water chemistry is the tip that makes the other nine easier. Heat speeds up every reaction in the pool, and evaporation quietly concentrates whatever does not leave with the water, so a balance that held all through April can be gone inside a week of July. Test weekly once the season starts. These are the numbers we work to:

• pH: 7.2 to 7.6, and in this region we aim at the lower half of that, for the reason set out in tip 2

• Free chlorine: 1 to 3 ppm

• Total alkalinity: 80 to 120 ppm

• Calcium hardness: 200 to 400 ppm, though local mains water often arrives near the top of it

• Cyanuric acid (stabiliser): 30 to 50 ppm, the most neglected reading on this list

Stabiliser deserves particular respect in this climate. Without it, sunlight strips unprotected chlorine from the water over a single bright afternoon, which is why a pool can test fine at breakfast and be defenceless by evening.

Tip 2: Manage the region's hard water

Mains water here typically carries 250 to 350 ppm of calcium and magnesium, dissolved out of the limestone the Algarve sits on. You tend to see the consequences before you see the cause: a chalky band along the tile line, water that clouds for no obvious reason, heaters and salt cells that give up earlier than they should. Scale on an electrode never announces itself. It simply makes the cell work harder until one day it stops working.

Hold pH in the lower half of its range and run a sequestering agent through the season. Scale that has already set is a job for proper descaling rather than a brush and determination, and the longer it sits the more of the surface it takes with it when it finally lifts. One consequence is worth spelling out: every top-up brings fresh calcium into the pool, so water you lose is also hardness you gain.

Tip 3: Run the filtration properly

Many of the filters we inspect are run for too few hours to save electricity, which is false economy of the purest kind: the savings are small and the green pool that follows is not. In summer the filter belongs on for 8 to 10 hours a day, and those hours should sit in daylight, when chlorine demand peaks and the water is warmest. Backwashing is not a diary task, it is a gauge reading: roughly 0.5 bar above the clean pressure. Baskets want emptying twice a week once things start blossoming and shedding. The media itself has a working life of three to five years, after which it channels, and water finds its way through without much happening to it.

Tip 4: Stay ahead of algae

Algae are opportunists. They want warmth and light, which July hands them without being asked, plus a lapse in attention, which is the only part of that list you control. Brush walls and steps weekly, because algae anchor where water circulates least, in the corners and behind the ladder. Keep chlorine consistently in range. Shock the pool every week or two through July and August even when the water looks perfect: by the time it stops looking perfect, you are no longer preventing anything, you are recovering. Do any shock treatment in the evening, so the sun does not burn off the chlorine before it has done its work. Our view after 18 years of green pool recoveries is unfashionable but consistent: we would rather see owners buy fewer chemicals and keep a stricter routine than the other way round.

Tip 5: Conserve water deliberately

Evaporation in a climate like this averages around 4.4 litres per square metre per day and peaks far higher in July (Hof et al., 2018, Water, vol. 10, no. 12). A cover is the single most effective answer: the US Department of Energy puts the reduction in make-up water at 30 to 50 percent, alongside 50 to 70 percent lower heating costs. An automatic pool cover makes covering effortless, which is what makes it consistent. Our client Paul had a solar cover fitted and told us afterwards he was amazed at how efficient it is; that reaction is typical, because nobody quite believes the evaporation numbers until the top-ups stop. And if the level drops faster than evaporation explains, test for a leak before the loss compounds.

Tip 6: Protect the equipment from the heat

Open the door of a pool equipment box in August and the air that meets you explains half the breakdowns we see. Pumps, heat pumps and control gear age far faster at 40°C in a sealed enclosure than they would in a ventilated one. Shade the technical area, keep the vents clear, and where the chemistry allows, programme the long pump runs for the cooler hours. Heat is a slow killer of pool equipment, and the prevention costs almost nothing.

Tip 7: Look after surfaces and tile lines

Clean the waterline weekly before scale and body oils bond to it, and brush surfaces regularly rather than waiting for visible growth. Established scale or staining on an older pool is usually a renovation conversation rather than a cleaning one; our pool refurbishment page covers when that makes sense. Adam, whose pool we retiled, put the outcome simply: with the new tiles the pool looks brand new.

Tip 8: Set up a holiday home pool to run without you

A pool with absent owners needs equipment that regulates itself and reports in. A salt chlorinator keeps sanitising steady without anyone dosing it, the INDYGO Pool Level system manages top-ups and shows consumption in its app, and a dependable weekly arrangement for physical care completes the picture. We have written a full guide to managing your pool remotely.

Tip 9: Spend less energy on the same swimming

A variable speed pump moving the same water more slowly for longer uses a fraction of the electricity of an old single-speed unit, LED pool lights draw far less than halogen, and a cover keeps in the heat you have paid for. For heated pools, a modern inverter heat pump paired with a cover is the efficient combination for this climate. The results are not abstract: Graeme had a new heater fitted and reached 28 degrees within twenty hours of switching on, and Adam, heating through a cool April with a heat pump and solar slats, was up to temperature in around 36 hours.

Tip 10: Keep the pool safe as well as clean

Chemicals belong somewhere cool, ventilated and locked, which in practice means not the sunniest corner of the pool house, where most of them end up. Where there are small children or pets, a physical barrier does the work that human vigilance cannot sustain for a whole summer. A removable safety fence with a self-closing gate gives that protection and comes down again afterwards, leaving the terrace as it was. Whatever safety equipment is on site, test it at the start of the season rather than in the moment it is needed.

Summer pool care in the Algarve rewards routine over heroics. Balanced water, a properly run filter, a cover on the pool and equipment that reports in will carry a pool through the hottest months in perfect condition. If any part of the setup needs attention, get in touch.

Frequently asked questions

How often should I shock my pool in an Algarve summer?

Every one to two weeks through July and August, even if the water looks clear, and always in the evening so sunlight does not consume the chlorine prematurely. Heavy bather loads and Saharan dust events justify an extra treatment.

Why does my chlorine level drop so quickly?

Strong ultraviolet light destroys unstabilised chlorine within hours. Keep cyanuric acid at 30 to 50 ppm to shield it, and cover the pool when it is not in use; less sunlight on the water means less chlorine consumed.

How do I prevent white scale on the waterline?

Hold pH at 7.2 to 7.4, use a sequestering agent monthly, and clean the waterline weekly before deposits harden. The region's limestone-fed water makes some scaling pressure permanent, so prevention is a routine rather than a one-off fix.

My holiday home pool turned green while I was away. How do I stop it happening again?

Automate what failed: a salt chlorinator for steady sanitising, automatic water level control, and remote monitoring so a fault announces itself early, combined with a reliable weekly arrangement for physical care. Our guide to managing a pool remotely covers the full setup.