Hot Tub Chemicals - User Guidelines

Hot Tub Chemicals - User GuidelinesHere at Pure-Spa we recommend following these care and maintenance guidlines.
All the chemicals you need in order to keep your hot tub in pristine condition can be purchased here

Hot Tub water Chemicals

Test chlorine levels to see if they are between 2-5 mg/l (ppm) and dose according to the instructions on the 'Stabilised Chorine Granules'. Or Test Bromine levels to see if they are between 3-4 mg/l ppm. Adjust brominator accordingly.

Test Hot Tub/Spa Water PH levels to see if they fall between 7.2 and 7.6. If not within these parameters use Pure-Spa pH Increase or Decrease according to instructions. If water is foaming use Pure-Spa Anti Foam.

Shock Hot tub with suitable oxidising agent such as Non chlorine shock (Oxygen Shock) or Spa Granular Shock (Calcium Hypochlorite).

Due to the build up of Total Dissolved Solids (TDS) the Hot Tub/Spa may need draining & refilling, this helps to protect against bacteria that can build up.

Clean Filter using Pure-Spa Filter Cleaner.

If you live in an area with hard water (high Calcium) add Pure-Spa Hot Tub Scale Control.

Periodically (Once every 3 months):

System FLush - use Pure-Spa Hot Tub System Flush to give yours spa plumbing system a good clean.

Clean hot tub cover - use Pure-Spa Hot Tub Surface Cleaner just spray on and wipe off using suitable cloth

Replace hot tub filter - Install a new filter we recomend only buying a original brand like Pleatco Pure see our Hot Tub filters section and use our helpful Filter Finder to identify the correct Filter

Water Balance
It is important to maintain the correct water balance to create the perfect conditions for you to relax in.

Sanitiser: A substance or process which kills or inhibits the muliplication of pathogenic organisms such as bacteria and moulds.

Sanitising of your hot tubs water is vital to kill bacteria and prevent algae growth. Levels should be checked regularly using Hot Tub Test Strips or pool tester kits. You can use either Chlorine or Bromine to adjust the levels.

Bromine: Using Bromine is a very effective Hot Tub/ Spa Water sanitiser. It comes in tablet forms making it easy to apply to the water.

The ideal Bromine level is between 3 - 6mg/l

Chlorine: Using Stabilised Chlorine granules is another effective Hot Tub/Spa sanitiser. It comes in granule forms which dissolve very quickly in the hot tubs.

The ideal Chlorine level is between 2 - 5mg/l

Shock Treatment
This term describes adding additional oxidising agent for the purpose of destroying chloramines and algae. It should be carried out when bathers are not in the pool.

Oxidisation is essential to eliminate organic contaminants introduced by bathers. We recommend that you oxidise your Spa regularly using either Pure-Spa Non Chlorine Shock, or Pure-Spa Spa granular Shock. Oxidisation destroysodours and other organic contaminents such as perspiration, cosmetics and body oils. By doing this at least monthly it improves the comfort and hygiene for hot tubs users.

Non Chlorine Shock -Oxygen shock
A non chlorine shock designed as an alternative to using chlorine based materials. It does not over stabilise the Chlorine and is particularly recommended for Bromine systems where its use will reactivate the sanitiser. Add OXYGEN SHOCK at the rate of 12 grammes per 1000 litres of water. Predissolve in water and add to the Spa. Due to its fast dissolution, bathers can return to the water in 30 minutes

Shock Chlorine - Spa Granular shock
If pool water has problems of an algea build up or chlorine odour it may be necessary to increase the chlorine level from its normal 1 to 3 p.p.m to between 5 an 10 p.p.m. This treatment should be carried out without bathers in the pool and they should not be permitted to return until the chlorine level has dropped to its normal level. This process should kill microorganisms and algae and break down the Chloramines which are responsible for the undesirable chlorine odour. Use Spa Granular shock (Calcium Hypochlorite) as this is unstabilised and will release Chlorine quickly.

Calcium Hardness:
It is important to achieve the correct level of calcium in your water, the levels of which will vary depending on where you live and where your water supply comes from. Soft water tends to be low in calcium and hard water tends to be higher. Every time you top up or refill your hot tub with fresh water you need to check levels of calcium.

The ideal calcium hardness level for a hot tub is between 100 -200mg/l If the level in your hot tub is below this it could lead to corrosion damage. If you do find the level is low, then use Pure-Spa Hardness Increase to bring it up to the correct level. If the level in your hot tub is above this it can lead to the water appearing cloudy. As a result, calcium can be deposited on the tub shell, heater element, filter cartridge element and the pipe work within.

Total Alkalinity
This is a measure of all the alkaline materials in the pool water , it is present as a pH "buffer" Total Alkalinity depends on your water source and should be checked every time fresh water is added. The ideal Total Alkalinity for your Spa water is between 125 - 150mg/l If it stays between this it will prevent the pH of the water fluctuating and make the addition of chemicals easier to control TA lower than 100 p.p.m will cause the pH to fluctuate in an uncontrolled manner, we suggest using Pure-Spa pH Increase to raise levels. Levels higher that 200 p.p.m causes the pool water to resist pH changes due to "overbuffering". water can become poor in clarity and scale will form. To reduce this use Pure-Spa pH decrease.

pH Levels
If the pH of your water is too high, the efficiency of your Chlorine sanitiser will be reduced and you may have problems with scaling and cloudy water.

It is essential you regularly check the pH of your Spa water using Test Strips or test kits. The ideal pH range is between 7.4 -7.6, this is slightly alkaline which protects the hot tub and equipment. It also provides the most comfortable condition for hot tub users and has a good sanitising efficiency. If the pH level is below 7.4 use Pure-Spa pH Increase to raise the level and if the pH level is above 7.6 use Pure-Spa pH Decrease to reduce the level.

It is always better to make several small corrections and retest between additions.

ph Decrease - ("pH minus") An acidic material added to water to lower the pH.
ph Increase - ("pH plus") An alkaline material added to water to raise the pH.
pH measurement - This may be carried out by test sticks or papers, colourimeter test or by using a pH meter.

Control of Foam
Due to the vigorous circulation and aeration of spa water unsightly foam can appear on the surface of the water, especially when oils and lotions are in the water. To reduce the foam use Pure-Spa Anti foam regularly to prevent and control foaming. If the problem of foam continues after using Pure-Spa Anti Foam we recommend that you drain and refill with fresh water.

Cleaning your Hot Tub surface.
At the waterline, grease and bathing deposits can build up to create a scum line around the tub which provides an ideal breeding ground for bacteria and algae.
To remove these lines easily you should use a suitable cleaner such as Pure-Spa Hot Tub Surface Cleaner.

Cleaning the Filter Cartridge - You will be able to tell when the filter needs cleaning as the circulation within the hot tub will be reduced and the water cleanliness will change.

To avoid the inconvenience of the filter not working we recommend that it should be cleaned at monthly intervals or more if you use your hot tub heavily. Pure-Spa Hot Tub Filter Cleaner helps clean and restores filters to their full efficiency.

Cleaning inside the pipework
To remove the build up bathing deposits from inside the pipe work a plumbing system flush should be used at every water change. This will help to reduce the formation of biofilm and other organic grime. We recommend Pure-Spa Hot Tub System Flush.

Fragrances - It always a nice touch to add a fragrance to your hot tub water but never use ordinary bubble bath fragrance as this will create foam which is not good for your tub. Only ever use Non foaming Spa Fragrances that have been designed for use in Hot Tubs.



  • (Chlorine) 2-5 mg/l (ppm)
  • (Bromine) 3-6 mg/l (ppm)

pH 7.2 - 7.6

Total Alkalinity 80 - 160 mg/l (ppm)

Calcium Hardness Min 100 mg/l (ppm)

N.B. Spas fitted with devices such as ozonators will still need a residual
sanitiser (Chlorine/Bromine) for treating ongoing spa pollution.

Also read general spa safety tips and chemical safety tips in your Owner's
Guide and on chemical containers!.