Domakihub How to Test Pool Water and Keep Your Chemistry Right
A straightforward routine that keeps swimmers safe and extends the life of your pool.
Reviewed by Domakihub pool pros · 2026-06-23 · 5 min read
The video above walks you through the three main testing methods in real time; this guide gives you the step-by-step process so you can follow along and repeat it with confidence. Regular water testing is the single most important habit for any pool owner, whether you manage a private villa, a holiday rental, or a hotel pool in Greece. The Aegean climate means high UV exposure and heavy bather load during summer, so chemistry shifts faster than in cooler countries — testing twice a week is the baseline, not a luxury.
Why Pool Chemistry Goes Out of Balance So Quickly in Greece
Intense Mediterranean sunlight burns off free chlorine much faster than in northern Europe, often halving your residual within 24 hours. Combined with warm water temperatures and the salt content in coastal air, the conditions are ideal for algae blooms and bacterial growth if you let testing slip.
Holiday rentals and hotel pools face additional pressure: guest turnover means sunscreen, body oils, and sweat are introduced in concentrated bursts. A pool that tested fine on Monday morning can be unsafe by Wednesday afternoon if occupancy is high.
Choosing the Right Test Method
There are three practical options: test strips (fast but less precise), liquid drop kits (accurate and affordable), and digital photometers (lab-grade, used by professionals). For a private home pool, a liquid drop kit covering chlorine, pH, alkalinity, and cyanuric acid covers everything you need. Rental operators and hotels should keep a digital meter on site and send a sample to a certified lab at the start and end of each season.
Whichever method you use, always test at the same time of day — ideally in the morning before direct sunlight hits the water and before the day's swimmers arrive. This gives you a consistent baseline.
How to Test Your Pool Water in 5 Steps
- 1
Collect a water sample correctly
Use a clean 250 ml bottle or the sample tube from your test kit. Collect the water at elbow depth (roughly 40 cm below the surface) and at least 50 cm away from return jets or the skimmer. Surface water and jet-agitated water give skewed readings. Cap the bottle and bring it to a flat surface out of direct sunlight before you open any reagents.
- 2
Test free chlorine and combined chlorine
Add the DPD No.1 reagent for free chlorine and read the colour against the comparator. A healthy range is 1–3 ppm (parts per million). Then add DPD No.3 to check combined chlorine (chloramines). If combined chlorine exceeds 0.5 ppm, you will smell the classic harsh chemical odour and swimmers will experience eye irritation — a shock treatment is needed regardless of what your free chlorine reads.
- 3
Measure pH
Add the phenol red indicator and compare the resulting colour to the chart. Target pH is 7.2–7.6. Below 7.2 the water turns corrosive: it irritates skin and eyes and damages grout, metal fittings, and heat exchangers. Above 7.8 chlorine becomes ineffective, giving you a false sense of security. Adjust with pH-minus (sodium bisulphate) or pH-plus (sodium carbonate) in small increments and re-test after the circulation pump has run for at least two hours.
- 4
Check total alkalinity and cyanuric acid
Alkalinity (target 80–120 ppm) acts as a pH buffer — if it is too low, pH will bounce wildly with every splash of rain or topping-up water. Cyanuric acid (CYA, stabiliser) protects chlorine from UV degradation; aim for 30–50 ppm for an outdoor pool. If CYA climbs above 80 ppm (common after over-stabilising with trichlor tablets over several seasons), chlorine is effectively neutralised and the only fix is a partial drain and refill.
- 5
Record results and take action
Log every reading in a simple spreadsheet or notebook with the date, time, and any corrections made. This record is invaluable for spotting trends — for example, pH consistently drifting upward may indicate that your fill water has very high alkalinity and you need to switch to a different balancing routine. For rental properties, a written log also demonstrates duty of care to guests and satisfies most local authority requirements in Greece under health and safety regulations for public and semi-public pools.
Rather have a pro handle it?
Get a vetted pool pro in your city — one number, booked in EN/EL/DE.
FAQ
- How often should I test my pool water in summer in Greece?
- At minimum twice a week for a private pool, and daily for a rental or hotel pool during peak season (June–August). High temperatures and heavy use in the Greek summer accelerate chemical consumption, so weekly testing that might be adequate elsewhere is not sufficient here.
- Can I use the same test kit for a saltwater pool?
- Yes, with one caveat: a saltwater chlorinator produces free chlorine from dissolved salt, so you still test for the same parameters (chlorine, pH, alkalinity, CYA). You will additionally want to check salt levels (target 2700–3400 ppm for most electrolytic cells) using a dedicated salt meter or test strips rated for salinity. Standard drop-kit tests for chlorine, pH, and alkalinity work exactly the same regardless of whether the pool is salt or traditionally dosed.
- My test strip shows low chlorine but the water looks crystal clear — is it safe to swim?
- No. Clarity is a poor indicator of safety. Water can appear perfectly clear while harbouring insufficient chlorine and dangerous bacteria, including E. coli. Always trust the test result over the visual. Add the appropriate dose of chlorine, run the pump for at least four hours, re-test, and only allow swimming once the free chlorine reads between 1 and 3 ppm and pH is within range.