How Many Chlorine Tablets Should I Put in My Pool?

Thanks to their convenience, reliability, affordability and ease of use, chlorine tablets are the go-to sanitisation method for many pool owners. As they’re slow-release, you can simply put them in your dispenser and leave them to do their thing. 

Getting the right dosage can also be more straightforward compared to using chlorine granules or liquid, as you won’t have to make any precise measurements; it’s just a question of how many tablets you need to suit the size and requirements of your pool. 

Chlorine tablets or granules?

How to Use Chlorine Tablets in Your Pool

No matter what kind of swimming pool chemicals you’re using, your first port of call should always be a careful review of the manufacturer’s instructions included on the product’s packaging. 

This will include clear instructions and advice on the appropriate dosages. We would also recommend never adding chlorine tablets directly to your pool water; instead, use applicators like floating dispensers or chlorine feeders to regulate the release of chlorine over time. 

While you should always refer to the manufacturer’s dosage advice first and foremost, there are some general guidelines you can follow that’ll help you understand the best practices for using chlorine tablets in your pool when just starting out. 

What Size Chlorine Tablets Do I Need? 

There are two primary tablet sizes you’ll come across: 

  • 20g chlorine tablets (1-inch diameter)
  • 200g chlorine tablets (3-inch diameter)

The smaller-sized tablets are most commonly used for hot tubs and small above-ground pools, while the larger tablets are more suitable for the majority of swimming pools. 

How Many Chlorine Tablets Should I Add to My Pool? 

The correct chemical dosages will primarily depend on the pool’s capacity – unsurprisingly, the bigger the pool, the more chemicals you will need. 

The very general rule for working out how many tablets you’ll need is to use one 200g/3-inch tablet for every 20,000 litres/5,000 gallons of water per week

If you’re not sure how much water your pool holds, you can use our pool volume calculator to quickly work it out.

Again, this is more of a general guideline rather than a golden rule, as it may also depend on environmental factors or the precise product you’re using. Most people will likely end up using 2-4 chlorine tablets a week to maintain a level of 1-3 ppm – for the precise dosage for your pool size and circumstance, refer to the instructions on your tub of chlorine tablets. 

Shop chlorine tablets for your pool

How Often Should I Add Chlorine Tablets to My Pool? 

Chlorine tablets are really useful for slowly releasing chlorine into your pool over several days to help maintain the chlorine level. For pool water the ideal range for chlorine is 1-3 ppm (for hot tubs it is 3-5 ppm). 

Our chlorine tablets will erode over 3-5 days, so you will need to retest your water and potentially add new chlorine tablets to your pool once or twice a week, depending on how much use your pool experiences and how much chlorine is used up. 

While using chlorine tablets can offer a more hands-off approach, you will still need to be diligent about testing your water regularly and making sure the tablets are doing the job they need to keep your pool thoroughly sanitised. Once your chlorine level dips below 1 ppm, you’ll need to up your water’s chlorine content (whether this is with tablets, granules or shock). 

What Happens if I Add Too Many Chlorine Tablets to My Pool? 

While it can be tempting to load up your dispenser with a bunch of tablets and leave them to do their thing, you do need to be careful about the dosage, as adding too many tablets can cause problems, especially if you don’t properly regulate the release rate. 

Too much chlorine in your pool can cause skin and eye irritation as well as damaging your pool equipment and affecting your water’s pH levels. There are ways to lower chlorine levels, but if you get the dosage spot on the first time around, you’ll only have to worry about increasing the amount of chlorine in your pool by adding your weekly tablets.

A diving board above clean pool water

Will I Need to Shock My Pool if I Use Chlorine Tablets? 

Tablets slowly release chlorine into your pool over time, while shock is faster acting and will raise your chlorine levels more rapidly. We would suggest using a pool shock treatment once a week or every other week to ‘reset’ your pool and eradicate the chloramines that would’ve built up in the water. 

As chlorine tablets are for regular maintenance and chlorine shock is a more intensive, less frequently required treatment that quickly gets your pool back into shape, you will need to use both to maintain a properly sanitised pool. 

pool chlorine vs shock

How to Use Floating Chlorine Tablet Dispensers

Once you’ve established how many tablets you need for the next few days, you can add them to your pool via a dispenser. These simple devices, sometimes also known as floaters or feeders, are easy to use and offer the most convenient method of delivering chlorine to your water. 

All you have to do is put the necessary tablets in the dispenser and close the lid. Then, adjust the gate on the bottom to regulate the amount of chlorine that’s released into the water. Once this is ready to go, put the dispenser on the pool’s surface – the movement of the circulating water will prompt the dispenser to move around the pool, dispersing the chemicals at the rate you’ve set. 

We recommend removing floating chemical dispensers from the pool when you’re swimming, as they’re better kept out of harm’s way. 

When it comes to chlorine tablet application and dosage, always consult the product’s instructions first before assuming a one-size-fits-all approach. If you require any chemicals to keep your pool sanitised and looking its best, look no further than our range of chlorine products, complete with fantastically discounted prices!