Pool chemicals are the invisible half of clear, healthy water. Seeing dozens of bottles and buckets on a shelf can be confusing, yet they all fall into a handful of functional families: pH adjusters, chlorine and disinfectants, algaecides, clarifiers and flocculants, metal sequestrants and a few special-purpose products. In this guide we explain what each family does, when you need it and in what order to use it. As a team that has managed villa pool water on the Çeşme peninsula for years, we have also included the safety rules and what to watch for in the region's hot, windy climate. The goal is simple: the right product, at the right moment, in the right amount.
Which values need to be in balance in pool water?
Before choosing a chemical, you need to know what you are aiming for. Pool water balance is defined by a few interconnected values, and when one drifts the others follow. When pH rises, for example, chlorine becomes markedly less effective; when alkalinity is low, pH swings from one day to the next. That is why chemical use always starts with measurement. For a quick daily check, a drop test kit for chlorine and pH is enough; if you want to track more parameters precisely, including alkalinity, hardness and stabiliser, a photometric reading such as the WaterLink ColorQ digital tester gives clearer results. The ranges below are the widely accepted industry targets.
- pH: 7.2–7.6 — the range where chlorine works efficiently and eyes and skin stay comfortable.
- Free chlorine: 1–3 ppm — the active chlorine that actually disinfects the water.
- Total alkalinity: 80–120 ppm — the buffer that keeps pH from swinging suddenly.
- Cyanuric acid (stabiliser): 30–50 ppm — slows the rapid breakdown of chlorine in sunlight.
- Calcium hardness: 200–400 ppm — protects surfaces and equipment from both corrosion and scaling.
What do pH adjusters do, and should you choose liquid or powder?
Pool water pH naturally tends to rise: fresh top-up water, some chlorine products, aeration and hot weather all push it upwards. Once pH climbs above 7.6, chlorine cannot do its job and the water starts to cloud and leave scale, which is why the most frequently used adjuster is a pH reducer. Liquid forms are easy to dose and blend into the water quickly; Quardex liquid pH reducer and Selenoid liquid pH reducer belong to this group. Pools with automatic dosing systems also generally use the liquid form.
Granular forms are easier to store and carry, and they give a controlled reduction. Quardex powder pH reducer and Selenoid powder pH reducer are first dissolved in a bucket of water and then spread across the pool while the pump is running. Whichever form you choose, do not try to drop pH in one large dose: add part of the label dose, let it circulate for a few hours and measure again. If your pH is low, below 7.2, what you need is not a reducer but a pH increaser; in that case checking alkalinity first usually reveals the root cause.
What is the difference between the chlorine and disinfection products?
Chlorine is the core disinfectant that neutralises bacteria, viruses and algae spores in pool water, and free chlorine needs to stay within 1–3 ppm at all times. Liquid chlorine (sodium hypochlorite) acts quickly, needs no dissolving and contains no stabiliser, so it suits daily top-ups without raising cyanuric acid levels. Quardex liquid chlorine and Selenoid liquid chlorine are suitable for this. Keep in mind that liquid chlorine can nudge pH up slightly and loses strength over time in light and heat, so store it somewhere cool and shaded.
Granular chlorine, with its high concentration, is used both for routine dosing and for shock chlorination, which means temporarily raising chlorine levels to recover the water after heavy use, rain or the first signs of green. Quardex 90% granular chlorine and Selenoid granular chlorine are practical options for these jobs. If you want continuous, steady disinfection, slow-release tablets make life easier: WTR multifunction chlorine tablets also help with clarifying and algae prevention alongside disinfection. Use the tablets as the product label recommends, for example in a floating chlorine dispenser, and never drop a tablet directly onto the pool floor or surface. Some granular and tablet chlorines contain stabiliser, so measure cyanuric acid as well during long-term use.
What is the difference between an algaecide and an algae remover?
Both products deal with the same problem but come in at different moments. An algaecide is a protective product dosed regularly alongside correct chlorine and pH; it stops algae spores from settling and multiplying in the first place. It makes sense to add it to your weekly routine especially during hot summer weeks, busy periods or when the villa stands empty for a long time. Selenoid algaecide, the concentrated Poolbox algaecide and Quardex algaecide belong to this group. An algaecide does not replace chlorine; if disinfection is weak, it cannot stop the water turning green on its own.
An algae remover, on the other hand, is used once the problem has appeared. Quardex algae remover breaks down algae layers that have formed on walls and floor, speeding up the water's recovery. For an effective result, first balance pH, then shock chlorinate, brush the walls and clean the filter; the algae remover completes this process. Returning to regular algaecide use once the water has recovered goes a long way towards stopping the problem from coming back within a few weeks. We explain step by step how to bring a green pool back in our guide to green pool water.
For cloudy water, should you use a clarifier or a flocculant?
If your values are balanced yet the water looks dull, the problem is usually particles too fine for the filter to catch on its own. For mild cloudiness you use a clarifier: these products clump fine particles together so the filter can hold them, while the pump keeps running as normal. Quardex clarifier, Selenoid clarifier and Poolbox clarifier are used for this. With a few days of filtration the water noticeably sparkles; during this time watch the filter pressure and backwash if needed.
For heavy cloudiness a flocculant works faster. Selenoid flocculant and Poolbox flocculant bind suspended dirt into clumps and drop it to the pool floor. After adding the product, the pump is left off for the time stated on the label, and the sediment on the floor is then vacuumed out, ideally with the filter set to waste; otherwise the sediment simply mixes back into the water. For sand-filter pools where you want a gentle, continuous effect, Poolbox flocculant tablets go into the skimmer basket and dissolve slowly, supporting filter performance.
When do you need metal and stain preventers?
In pools filled from a well or a water tanker, with older copper-containing plumbing, or after long-term use of certain algaecides, metals such as iron, copper and manganese can build up in the water. When these metals react with chlorine, the water may take on a greenish or brownish tint and stubborn stains form on surfaces and grout lines. Metal sequestrants bind the dissolved metal ions and prevent staining. Quardex anti-ion and Selenoid metal sequestrant are well suited to use at first fill and after topping up from an outside source. Alongside these, the mineral ion ball is a supporting product that gradually releases minerals into the water to help keep it balanced; think of it as a helper to chemical balance, not a replacement for it.
How are alkalinity reducer and cleaning acid used?
When total alkalinity rises above 120 ppm, pH keeps climbing and creeps back up soon after every dose of pH reducer; that is a sign the problem lies with alkalinity, not pH. Selenoid liquid alkalinity reducer gradually brings high alkalinity down into the 80–120 ppm range. Correcting alkalinity can take several days, so measure both alkalinity and pH after each application. Because an alkalinity reducer is itself acidic, it pulls pH down at the same time, so make sure pH has not dropped below 7.2 after application.
Cleaning acid, on the other hand, is meant for surfaces rather than the water: Selenoid cleaning acid is used to dissolve mineral deposits such as the scale ring at the waterline and residue on stone and grout. Always follow the dilution ratio on the label, wear gloves and safety glasses, rinse the surface thoroughly afterwards, and never use the acid in the same container or at the same time as a chlorine product. As the Seçkin Havuzculuk team, we recommend doing acid surface cleaning, where possible, with the pool empty or the water level lowered, and in a well-ventilated setting.
Which special products are used for salt cells and chloramines?
In saltwater pools, chlorine is produced in an electrolysis cell. Over time, scale builds up on the cell plates and chlorine output drops; Selenoid salt cell cleaner dissolves these deposits and keeps the cell working efficiently. How often you clean depends on your water hardness and should follow the manufacturer's instructions. During cleaning, switch the system off, remove the cell as the manufacturer describes and use the liquid at the ratio given on the label. When you notice an unexpected drop in chlorine output, the cell plates are usually the first place to check.
The sharp chlorine smell and stinging eyes around a pool usually come not from too much chlorine but from combined chlorine (chloramines), formed when chlorine binds with sweat and cosmetic residue. Poolbox combined chlorine remover breaks these compounds down and restores the water's freshness. Keeping the pool surroundings clean is part of water quality too: Quardex poolside surface cleaner removes dirt and residue from the pool edge and foot-wash areas, reducing the dirt carried into the water.
In what order are pool chemicals added, and how do you use them safely?
Whether chemicals reinforce or cancel each other out depends largely on the order in which they are added. The general flow is: measure first, then balance alkalinity and pH, then disinfect, and only then move on to clarifying and preventive products. Between each product, give the water time to mix with the pump running. You will find the full weekly routine in our article on how to maintain a pool. On the safety side there is no room for compromise; the rules below apply to every product.
- 1. Test: do not add any product without first measuring chlorine, pH and alkalinity.
- 2. Adjust alkalinity, then bring pH into the 7.2–7.6 range.
- 3. Disinfect with chlorine; if shock chlorination is needed, do it in the evening, because sunlight quickly consumes part of the chlorine.
- 4. Once chlorine is balanced, add algaecide, clarifier or flocculant.
- Never mix chemicals together; add each product separately, using a separate, clean container.
- If dilution is needed, always add the chemical to water; never pour water onto the chemical.
- Never store acid-based products next to chlorine products; contact between them can release dangerous chlorine gas.
- Keep products in their original packaging with lids closed, away from children and pets, in a cool, dry, well-ventilated place; wear gloves and goggles when applying them.
- Do not add chemicals while anyone is swimming; before swimming resumes, confirm by measuring that values are back in the normal range.
What should you watch for when using chemicals in the Çeşme and Alaçatı climate?
The long, sunny and hot summer season of the Çeşme peninsula noticeably increases chlorine consumption. Unstabilised chlorine breaks down quickly under strong sun, so keeping cyanuric acid in the 30–50 ppm range lets chlorine keep working throughout the day. However, constant use of stabilised tablets and granules raises this value too far over time and reduces chlorine's effectiveness, so regular measurement through the season is essential. The imbat and lodos winds carry dust, pollen and leaves into the water and put extra load on the filter; in windy spells it helps to clean the skimmer and filter more often and to reach for a clarifier when needed. Fresh water added to make up for heavy evaporation also shifts pH and alkalinity. In rental villas, chloramine levels and chlorine demand rise as the number of bathers grows.
Near the shore, salty sea air and humidity gradually corrode metal packaging caps, dosing pumps and fittings in the plant room, and chemical fumes speed this up. That is why you should store your chemicals in a shaded, ventilated plant room rather than on a sunny terrace, with lids tightly closed and off the floor. Because heat makes chlorine products lose strength, it also makes sense not to stock more than you need at the start of the season. When the villa will stand empty for weeks, balancing the values and adding an algaecide before you leave reduces the risk of coming back to a green pool. If you would like us to manage your water chemistry for you throughout the season, take a look at our professional pool maintenance in Çeşme service, and you can find the products you need on our full range of pool chemicals page.
Common questions.
Which chemicals does a pool need?
Every pool has two core needs: a pH adjuster that keeps pH within 7.2–7.6 and chlorine that holds free chlorine at 1–3 ppm. Most pools add a regularly dosed algaecide to these. Clarifiers, flocculants, metal sequestrants, alkalinity reducers and combined chlorine removers are used as needed, depending on test results or the problem that appears.
In what order are pool chemicals added?
Test the water first. Then bring alkalinity into the 80–120 ppm range, followed by pH into 7.2–7.6. Once the values are balanced, disinfect with chlorine, doing any shock chlorination in the evening. Finally, add supporting products such as algaecide, clarifier or flocculant. Let the water mix with the pump running between each product, and never add products together.
What are the ideal pH and chlorine levels?
The widely accepted range is 7.2–7.6 for pH and 1–3 ppm for free chlorine. When pH rises above this range, chlorine loses effectiveness; when it falls below, the water irritates eyes and skin and corrodes equipment. To hold these two values reliably, total alkalinity should also stay within 80–120 ppm and cyanuric acid within 30–50 ppm.
Can pool chemicals be mixed, and how should they be stored?
No, pool chemicals must never be mixed; contact between acid-based products and chlorine in particular can release dangerous chlorine gas. Add each product separately, and when diluting, add the chemical to water. Store products in their original packaging with lids closed, out of children's reach, in a cool, dry, ventilated place. Keep acid-based products on separate shelves from chlorine products.