200g trichlor tablets are the best choice for private pools between 10,000 and 60,000 litres. They dissolve slowly over 7 to 10 days, are simple to dose via a floating dispenser or skimmer and cost approximately EUR 6 to EUR 8 per kg.
Which type of chlorine is best?
| Type | Active chlorine | Dissolve time | Cyanuric acid | Best for |
|---|---|---|---|---|
| Trichlor tablets 200g | 90% | 7 to 10 days | Yes | Routine pool maintenance |
| Trichlor tablets 20g | 90% | 1 to 2 days | Yes | Small pools, fine-tuning |
| Calcium hypochlorite granules | 65 to 70% | Immediate | No | Shock treatment |
| Sodium hypochlorite (liquid) | 12 to 15% | Immediate | No | Shock treatment, fast response |
| Dichlor granules | 56% | Immediate | Yes | Shock treatment |
For daily use, 200g trichlor tablets are the best choice. For shock treatments, use calcium hypochlorite or liquid chlorine: they contain no cyanuric acid and are immediately active.
Our pick: Bayrol 200g chlorine tablets
Bayrol is a reliable European brand with consistent quality. Their 200g tablets have a high chlorine content (90%), dissolve evenly and are widely available.
Chlorine Tablets 200g (5 kg)
BayrolSlow-dissolving chlorine tablets for use in skimmer or floating dispenser. 5 kg for a full season.
- Slow dissolving
- Easy to dose
- Good price per kg
- Slightly lowers pH over time
Interline Chlorine Tablets 200g (5 kg)
InterlineTrichloro tablets of 200 grams with 90 percent active chlorine. 5 kg of stock covers a full season in pools up to 50,000 litres.
- 90 percent active chlorine
- Slow 7 to 10 day dissolve time
- From an established Dutch pool specialist
- Also available in smaller packs
- Higher price per kg than no-name options
- Contains cyanuric acid (CYA)
Pool Lab Tabs 200g Chlorine Tablets (5 kg)
Pool Lab25 trichloro tablets of 200 grams, totalling 5 kg. Same formulation as premium brands at roughly half the price.
- Half the price of major brands
- 200 gram 90 percent trichloro
- Same dissolve time as Bayrol and Interline
- Good pick once you know your usage
- Lesser-known brand
- Less Dutch packaging detail
How much do you need per season?
Consumption by pool volume:
| Pool volume | Normal use | Heavy use |
|---|---|---|
| 10,000 litres | 1.5 kg | 2.5 kg |
| 25,000 litres | 3 kg | 5 kg |
| 50,000 litres | 5 kg | 8 kg |
“Normal use” = 1 to 2 swimmers, 3 times per week. “Heavy use” = more swimmers, daily, hot summer.
Stabilised vs. unstabilised chlorine
Trichlor tablets contain cyanuric acid (CYA) as a stabiliser. CYA protects chlorine from UV breakdown: without stabiliser, sunlight destroys 90% of free chlorine within 2 hours. With CYA at 30 to 50 mg/l, half the chlorine remains after 6 hours of direct sunlight.
The downside: CYA accumulates in the water because it does not evaporate or break down. Each dissolved 200g tablet adds roughly 6 grams of CYA to the water. In a 25,000-litre pool consuming 5 kg of trichlor per season, the CYA level rises by approximately 120 mg/l. Above 80 mg/l CYA, the effectiveness of chlorine drops dramatically: this is called chlorine lock or chlorine demand. Free chlorine is present but bound to CYA and unavailable for disinfection.
Calcium hypochlorite contains no CYA. It is therefore the preferred choice for shock treatment when you need rapidly available active chlorine without pushing CYA levels higher.
Hypomen Fast-Acting Chlorine Granules (5 kg)
HypomenCalcium hypochlorite granules for shock treatment. Dissolves instantly and acts within hours — without raising cyanuric acid levels.
- No CYA build-up in the water
- Active within 1 to 2 hours
- Tackles algae and cloudy water effectively
- 5 kg covers multiple shock treatments
- Never mix with trichloro (fire risk)
- Raises calcium hardness
- Requires pre-dilution in a bucket
Weekly dosing guide
One 200g tablet per 25,000 litres per week is the standard starting point. At temperatures above 28 degrees, heavy use (more than 5 swimmers per day) or after rain: increase to 1.5 to 2 tablets per week.
| Pool volume | Basic dose | Heavy use |
|---|---|---|
| 10,000 litres | 0.4 tablet | 0.8 tablet |
| 25,000 litres | 1 tablet | 2 tablets |
| 50,000 litres | 2 tablets | 4 tablets |
Always verify free chlorine with test strips. The tablet dosing is a starting point, not a guarantee. If free chlorine falls below 1.0 mg/l, add a tablet immediately or run a shock treatment. For full guidance on how to add chlorine to your pool , see our step-by-step guide.
Pool Power Mini Chlorine Tablets 20g (1 kg)
Pool PowerSmall 20-gram trichloro tablets in a 1 kg pack. Dissolve in 1 to 2 days — ideal for small pools or fine-tuning alongside 200g tablets.
- Fast acting thanks to 20g format
- Ideal for pools up to 10,000 litres
- Easy dosing in spas or kiddie pools
- 90 percent active chlorine
- Higher consumption than 200g tabs in large pools
- Only sold as 1 kg pack
Floating dispenser vs. skimmer
A floating dispenser distributes chlorine evenly throughout the day as it drifts across the surface. You can remove it easily before swimming so bathers have no direct contact with the concentrated tablet. Adjust the opening to control the dissolving rate.
The skimmer method is convenient: the tablet sits in the basket and is dissolved by the water flow. The risk: when the pump stops, concentrated chlorine water sits in the skimmer line and can attack PVC fittings and vinyl liners over time. Only use the skimmer method if the pump runs continuously.
Use a floating dispenser if you turn the pump off overnight or need to stop it regularly for maintenance.
Safe storage
- Store tablets dry and cool, preferably below 25 degrees
- In an unheated shed or cellar, stability deteriorates rapidly above 35 degrees
- Seal the container tightly after each use: humid air activates the oxidising properties and attacks the packaging
- Never store trichlor next to calcium hypochlorite, pH correctors or other oxidising agents. Contact between dry trichlor and calcium hypochlorite causes spontaneous combustion. Store in separate, sealed containers at least 1 metre apart
- Use gloves when handling tablets: direct skin contact with concentrated trichlor causes irritation
Warning
Never mix different chlorine products. Trichlor and calcium hypochlorite together cause a violent chemical reaction that can result in fire or explosion.
Safety: what to do at end of season
At the end of the season, remove all tablets from the dispenser and skimmer before winterizing. Never leave a tablet in a pool that is being partially drained: the chlorine concentrates as the water level drops and the chemical load on the remaining water becomes extreme.
Store unused tablets sealed in their original container in a cool, dry place over winter. Do not dispose of them in household waste or pour dissolved chlorine down storm drains.
Cost overview
A 5 kg bucket of trichlor tablets costs EUR 30 to EUR 45. A 20,000-litre pool at normal use consumes 3 to 4 kg per 20-week season. Total chlorine cost per season: EUR 25 to EUR 35.
To monitor chlorine levels accurately, pair your tablets with good test strips. See our best pool test strips comparison for the top options.
