Getting pool chemistry right isn’t complicated, but it does require consistency. In Cyprus, where summer temperatures regularly exceed 35°C, UV intensity is high, and the tap water is among the hardest in Europe, the margin for error is smaller than in cooler, softer-water climates. This post explains the three fundamentals — chlorine, pH, and total alkalinity — what they actually do, how they interact, and what to do when they drift out of range.
Why These Three Parameters Work Together
Chlorine, pH, and alkalinity aren’t independent dials you can adjust one at a time without consequence. They form a system. Chlorine kills bacteria and algae. pH determines how effective that chlorine actually is. Alkalinity stabilises your pH so it doesn’t swing wildly after every splash of rain or heavy bather load.
If your pH is too high, your chlorine becomes largely inactive — you can have a perfectly dosed pool that is still growing algae. If your alkalinity is too low, your pH will bounce around unpredictably. This is why professionals test all three, not just chlorine, and why cheaper test strips that only measure chlorine give you an incomplete picture.
Chlorine: Getting the Dose Right in Cyprus Conditions
The target range for free chlorine is 1–3 ppm (parts per million). In a private home pool used daily in July, you’ll probably be running toward the higher end. In a lightly used holiday villa pool, the lower end may be fine — but only if other parameters are balanced.
The UV problem
Cyprus receives more annual sunshine than almost anywhere else in Europe. UV from sunlight destroys unstabilised chlorine rapidly, sometimes within hours. This is why cyanuric acid (CYA), sometimes called chlorine stabiliser, matters here more than it does in, say, Germany. CYA protects chlorine from UV degradation. The recommended range is 30–50 ppm. Too little and your chlorine burns off before it can do its job. Too much and chlorine becomes less effective even at correct levels — a problem known as chlorine lock.
Saltwater pools and Cyprus heat
Many Cyprus pools use saltwater chlorination systems. These are low-maintenance in principle, but the cells work harder in high temperatures and can struggle to keep up during peak summer. Check your salt cell output more frequently from June through August, and don’t assume the system is coping just because it’s switched on.
pH: The Number That Controls Everything Else
Target pH is 7.2–7.6. This is the range at which chlorine is most active, surfaces and equipment are least at risk of damage, and the water is comfortable for swimmers.
What pushes pH up in Cyprus
Hard water is the main culprit. Cyprus tap water is rich in calcium carbonate — a consequence of the island’s limestone geology — and this drives pH upward over time. Refilling your pool with tap water, topping it up after evaporation (which is significant during summer), and the breakdown of certain chlorine compounds all push pH higher. In practice, many pool owners in Cyprus will be adding pH reducer (sodium bisulphate or hydrochloric acid) more regularly than they add pH increaser.
Signs of high pH
Cloudy water is often the first sign. You may also notice chlorine-resistant algae, scale forming on the waterline, and a stinging sensation in swimmers’ eyes despite what seems like adequate chlorination. These are all indicators of elevated pH, not necessarily low chlorine.
Total Alkalinity: The Buffer Your Pool Needs
Total alkalinity (TA) is not the same as pH, though the two are related. TA measures the water’s ability to resist pH changes. Think of it as the shock absorber in the system.
The target range is 80–120 ppm. If TA drops below 80 ppm, your pH becomes unstable — one heavy rainfall or a large bather load can swing it several tenths of a point in either direction. If TA rises above 150 ppm, it becomes difficult to adjust pH at all, and you may find yourself adding large quantities of acid with little visible effect.
Adjusting alkalinity
To raise low TA, you add sodium bicarbonate (baking soda). To lower high TA, you add muriatic acid, which is best added in concentrated doses to a specific area of the pool rather than broadcast across the surface — this technique targets TA without dropping pH as sharply.
In Cyprus, because of hard water, high TA is the more common problem. You may notice scale building up faster than expected, particularly around jets and on heating elements. This is often a joint consequence of high TA and high calcium hardness, and both need to be managed rather than just one.
Testing and Timing: A Practical Routine
Test your water at least twice a week in summer, and once a week at minimum during cooler months. Early morning testing gives the most accurate chlorine reading — UV hasn’t had a chance to deplete it yet. If you use a liquid drop test kit rather than strips, your readings will be more reliable.
After a dust storm — which in Cyprus can deposit significant Saharan sand and organic matter — test immediately and expect to shock the pool. The same applies after an unusually heavy bather load or a period of particularly high temperatures.
A good testing order: test TA first, adjust if necessary and wait, then adjust pH, then check chlorine. Adjusting TA tends to move pH slightly, so correcting it first avoids unnecessary extra work.
We Can Take This Off Your Plate
If testing twice a week and balancing three interdependent parameters sounds like more work than you signed up for, that’s exactly what a professional maintenance service is for. Pool Cleaning Cyprus serves homeowners, villa owners, and holiday rental managers across Limassol, Paphos, Nicosia, and Larnaca. We test, balance, and treat your pool on a regular schedule so you don’t have to think about it.
Call or email us to arrange a service visit or discuss an ongoing maintenance plan.