Why a PH and Chlorine test kit is not enough...
4 Nov 2026 · @CDS
Most pool owners (and even some pool maintenance companies!) test two things: pH and chlorine. A few drops in a little plastic tester, a quick look at the colour, and the job feels done. But a pool that "passes" that test can still turn green, go cloudy, sting your eyes or slowly eat away at your equipment, mostly the later.
The reason is simple. pH and chlorine are only two parts of a balanced pool, and they depend on several other readings that a basic kit never shows you. Aside from your PH reading, if your "TOTAL alkalinity" is off, then all your other readings are false. Here's what you're missing, and why our 7-in-1 dip test strips give you the full picture in about 30 seconds.
The problem with a basic colour tester
A standard two-chamber kit tells you roughly how acidic the water is and roughly how much chlorine is in it. That's useful, but it leaves big blind spots:
It can't tell good chlorine from used-up chlorine.
Most basic kits measure total chlorine. A pool can show a healthy reading while much of that chlorine is already spent and no longer sanitising.
It can't tell you why your pH keeps drifting.
If you're adding pH reducer or increaser every week, the real cause is usually alkalinity, which a basic kit doesn't measure.
It says nothing about stabiliser.
Too little and the sun burns off your chlorine in hours. Too much and your chlorine stops working, even at a "good" level.
It ignores water hardness.
Hard water leads to scale on tiles, heaters, filters and electrolysis cells. Soft water can etch plaster and grout.
In short, a basic tester shows you symptoms. It rarely shows you the cause.
What our 7-in-1 strips measure
One dip gives you a reading for every key part of your water balance:
pH – how acidic or alkaline the water is. When this takes a knock, swimmers get red eyes and itchy skin, and your chlorine loses much of its strength.
Free Chlorine (FC) – the chlorine that's actually available to kill bacteria and algae. This is the number that keeps your pool safe.
Total Chlorine (TC) – free chlorine plus chlorine that has already reacted with sweat, sun cream and other contaminants. Comparing TC with FC tells you how much of your chlorine is "used up"and often what has happened to your pool between our visits.
Total Alkalinity (TA) – the water's buffer. It holds pH steady, so if TA is off, your pH will keep bouncing around no matter how much you adjust it.
Total Hardness (TH) – the amount of calcium and magnesium in the water. It decides whether your pool leans towards scaling or towards eating into surfaces. Don't forget, our water is extremely hard here in TRNC.
Cyanuric Acid (CA) – also called stabiliser. It shields chlorine from the sun, but too much locks it up. Due to our climate, your pool will occasionally need to be diluted to get this reading down.
Why the readings only make sense together
Pool chemistry is a balancing act. Change one thing and others move with it. Seeing all six readings at once lets you fix the cause, not just the symptom.
Alkalinity controls pH. If your pH won't stay put, check TA first. Correct the alkalinity and the pH usually settles on its own, saving you chemicals and guesswork.
Stabiliser decides how hard your chlorine works. Chlorine with no stabiliser can be burned off by strong sun in a few hours. But as stabiliser builds up over the season, you need more free chlorine to get the same effect. Without a CA reading, you can't tell whether you need more chlorine or a partial water change.
The gap between total and free chlorine is a warning sign. When TC is well above FC, your pool has a build-up of combined chlorine (chloramines). That's what causes the strong "chlorine smell" and stinging eyes, and it usually means the pool needs shocking due to a contaminant. This is the classic moment when customers who don't fully understand this bit of chemistry will wag the finger at the pool staff for over-chlorinating, when we know its the opposite and usually the little ones have not been leaving the pool for toilet breaks (at least we hope its just the little ones!!!) and of course there are many other contaminants which can cause this.
pH, alkalinity and hardness together decide scaling. High readings across all three in warm water is a recipe for white crust on tiles, cloudy water and clogged filters and heaters.
Why it matters even more in North Cyprus
Our climate is tough on pools. Long, hot summers and strong sun burn through chlorine fast, so stabiliser levels really matter. High water temperatures speed up scaling, especially as water evaporates and minerals become more concentrated. And many properties fill and top up with hard water, which pushes calcium levels up year after year.
A basic pH and chlorine test simply can't keep up with those conditions. Testing all six readings means you catch problems early, before they turn into a green pool, a scaled-up heater or a costly repair.
Ideal ranges at a glance
Use these as a general guide for a chlorine pool. Your pool's surface and equipment may call for slightly different targets.
Reading | Ideal range | If it's too low | If it's too high |
pH | 7.2 – 7.6 | Stinging eyes, corrosion | Weak chlorine, scaling, cloudy water |
Free Chlorine (FC) | 1 – 3 ppm | Algae and bacteria growth | Skin and eye irritation |
Total Chlorine (TC) | No more than 0.5 ppm above FC | — | Chloramines: smell, red eyes, needs shocking |
Total Alkalinity (TA) | 80 – 120 ppm | pH swings, corrosion | pH creeps up, scaling |
Total Hardness (TH) | 200 – 400 ppm | Etched plaster and grout | Scale on tiles, heaters and filters |
Cyanuric Acid (CA) | 30 – 50 ppm | Sun burns off chlorine fast | Chlorine "locked", algae despite good readings |
Using the strips: quick and easy
Take a sample from about elbow depth, away from the skimmer and return jets.
Dip a strip for a couple of seconds, then remove it and hold it level. Don't shake it.
Wait for the time shown on the pack, then compare each pad with the colour chart in good natural light.
Note down your readings so you can spot trends over the weeks.
Test at least once a week in winter and two or three times a week in summer, plus after heavy use, a party or a big rainstorm. Keep the tub tightly closed and out of the sun so the strips stay accurate.
CDS offers regular pool maintenance throughout Northern Cyprus, from twice-weekly summer visits to annual pool health checks. Get in touch and we'll keep your water clear, safe and balanced all year round.
North Cyprus property, sorted!
Call: +905488444999
Email: info@cdscyprus.com
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