All your Hot Tub Chlorine Questions

The good news is whichever method of chlorine you use to stabilize the water in your hot tub, the costs are pretty similar.

If you opt for the SpaChem Spa Chlorine Granules, a 1kg tub will currently cost you from £16.92. If, however, you prefer to use the SpaChem Spa Chlorine 20g tablets, a 1kg tub will currently cost you from £14.83.

So luckily, on this occasion, price isn’t a huge influencer.

Its a very clear NO with regards to mixing the two sanitisers, when managing your hot tub water you need to use either or and not both together.  Bromine Granules and Bromine Tablets are fine to use together and similarly Chlorine Granules with Chlorine Tablets.  Please do not mix the two sanitizers.


Chlorine works by actively destroying any contaminants in the water of your hot tub. Whilst it breaks down the bacteria from the inside out, it dissolves in the water to form a waste product called chloramine.

By adding chlorine in your hot tub at least weekly, you will be able to keep chloramine at bay. You will know if you have a surplus of chloramine in your hot tub water as this is the chemical that has the notorious reputation for its unique smell, for causing stinging in the eyes and for drying the skin.

If the chlorine that you are adding as your hot tub sanitiser needs a helping hand, you can eliminate the number of chloramines in your water by doing a chlorine shock treatment. To help keep your water crystal-clear and ready to use, you will want to do this chlorine shock treatment regularly.  There are two types of shock which we will cover in our next blog, but calcium hypochlorite and an oxidizing shock call Non chlorine shock granules.

As both products are chlorine based, they are essentially and when used correctly, as effective as each other at controlling the bacteria and sanitizing the water in your hot tub.

The key to achieving the perfect balance and level of control is to ensure your hot tub water maintains a chlorine level of 3-5ppm.

Chlorine tablets slowly dissolving in either a floating dispenser or feeder device ensure that you have a constant supply of chlorine entering your water. This method still needs to be monitored and the flow of the devices adjusted to maintain the perfect levels.

Chlorine granules added directly with their rapid dissolving properties support a more instant adjustment to the chemical levels in your hot tub water. However, if your hot tub is left unattended for a period of time, or you are unable to monitor and adjust the levels daily the chlorine demand of your water could be compromised.
It goes without saying that care and attention must be taken when using all hot tub chemicals and this is the case for both chlorine tablets and chlorine granules.

Due to the way that they are manufactured, chlorine tablets are more acidic than chlorine granules. It is therefore important if you choose to use chlorine tablets that the floating dispenser is removed from your hot tub before you glide in.

The main risk with regards to chlorine tablets or chlorine granules not being used correctly is high elevated chlorine levels due to overuse and chlorine lock rendering the hot tub not useable. The second factor is correct pH & total alkalinity levels not being maintained at the right levels which will create an environment that will cause you tub to become too acidic or too alkaline, which will mean you burning through chlorine at a high rate.

Chlorine Mini Tablets 1kg, AS-YVAJ-0D39

Hot tub chlorine mini tablets are slow dissolving and specifically formulated for the disinfection of Spa and Hot Tub Water, swimming pools. These tablets should be dosed via a specific floating dispenser or an erosion feeder device.


Less expensive than bromine 

Ordinarily, chlorine is over 20% cheaper per kg order of tablets than the same amount of bromine tablets. This makes it a great value option for smaller or budget-conscious businesses. Here at SpaChem ™, we have a range of chlorine and bromine tablets to suit every business – discover more here. 

Stronger staying power in sunlight 

The active sanitiser in your pool or hot tub is affected by water temperature and sunlight. The higher the temperature, the faster the chlorine will 'burn off' or dissipate. One way to counteract this is to stabilise or protect the chlorine with cyanuric acid. This keeps the chlorine in the desired location within your pool or hot tub while it performs its job.  

Higher percentage of available sanitiser 

Each chlorine tablets contain Trichloroisocyanuric Acid. This has up to 90% available chlorine to actively sanitise your area. In comparison, a standard bromine tablet contains BCDMH at quantities of approximately 70%. This difference makes chlorine, kilo-for-kilo, a more potent option. However, it is worth noting that the free chlorine level of most tablets can drop off quicker than with bromine. 

Side note: Our Spa Bromine Tablets contain a BCDMH level of 90% - in line with standard chlorine tablets. 

Chlorine is convenient

When it comes to the initial setup of your hot tub or a water change cycle, the only consideration needed is how much chlorine you need. The application process is quick and simple. In comparison, bromine needs time to create bromides before it will register on a testing strip. 

Please ensure that, whenever you are applying chemicals to your spa, hot tub or pool, you wear appropriate PPE and follow all instructions. For more information regarding this, please feel free to contact our helpful and experienced team. 

Chemical Specification
UN Code 2648
How to use
Instructions 1. Maintain the pH balance between 7.4 – 7.6 2. On STARTUP and COMMISSIONING of new water always use SPA CHLORINE GRANULES to Shock Dose the water to a minimum of 20 PPM with circulation/blowers on and all covers off. 3. Test the water using a CHLORINE test kit, the ideal reading is between 4 – 6ppm. 4. Use 2 Spa Chlorine Mini Tablets in either a floating dispenser or erosion feeder to treat up to 1500lt of water. 5. Monitor the Chlorine readings, you may have to adjust the flow on the dispenser/feeder. 6. If you experience difficulties please contact your local dealer.
Precautions • Always ensure bathers are out of the water when adding chemicals. • Never mix with any other chemicals including cleaning products, weed killers, and chlorine products, as a dangerous reaction may occur. • Always handle products in a well-ventilated area. • Always wash hands thoroughly after handling chemicals. • Store in a cool, dry, well ventilated, secure place. Ensure chemicals do not become damp in storage. • Instructions and dosages given are a guide to the most effective use.
Warning • This container must not be used or contaminated with any other materials.

Write a review

Please login or register to review

SpaChem Small Chlorine Tablets 1kg

  • Brand: SpaChem
  • Product Code: SpaChem
  • Availability: 55
  • • : Chlorine Tablets are slow dissolving.
  • • : Small 20g Trichlor Chlorine Tablets.
  • • : Hot Tubs & Small Swimming Pools.
  • • : Dispenser, skimmer or in-line feeder.
  • • : Dissolve over a period of 4-10 days.
  • £17.83
  • £14.83

  • Ex Tax: £12.36

Related Products

Spa Chlorine Granules 1kg

Spa Chlorine Granules 1kg

Spa Chlorine Granules are rapid dissolving and are specifically formulated to disinfect Spa and Hot ..

£15.04 £18.04 Ex Tax: £12.53

3 in 1 Test Strips 1 x 50 (Chlorine)

3 in 1 Test Strips 1 x 50 (Chlorine)

A quick and easy way to test your spa water, these test strips will check free chlorine, pH and tota..

£10.79 £14.62 Ex Tax: £8.99

SpaPal - Inline Dispenser

SpaPal - Inline Dispenser

SpaPal inline tablet feeder for Chlorine or Bromine tablets. (trade discounts available on box quant..

£28.30 Ex Tax: £23.58

Tags: Chlorine Mini Tablets, Spa Chlorine Tablets, 20g Chlorine Tabs, Chlorine Dispenser Tablets

Help & Support Chat

Hi, Thanks for contacting us, we have a couple of departments that can help in specific areas, select below.