Pool Chemical Advice

Our Pool Chemical Guide has everything you need to know from recommended pool chemical dosage to algae control to help work out your pool's volume of water for accurate chemical measurements.

We recommend ClearWater® chemicals for our pools as they are designed for and continuously tested on Bestway pools. All dosage and application recommendations are based on ClearWater® pool chemicals and you should always refer to the instructions and warnings included with each product before using.


Are you having problems with your pool water? If so check out the problem and symptoms in the table below.

Green / Cloudy Water / Slippery SidesAlgaeShock dose with chlorine (see Getting Started) and add Algaecide.
Too much chlorineOverdose

1. Drain pool to minimum mark and re-fill with fresh water to maximum mark, this will help to dilute the excess chemical.

2. Remove cover from pool to allow evaporation of the chemical (keep the pool filter running constantly).

PH hard to controlAlkalinity too low or too high1. Test Alkalinity levels and adjust if required.

2. Test pH levels and adjust accordingly.
Can't maintain chlorine levelspH and Total Alkalinity are probably not balanced

Use the ClearWater test strips to test the water. 

Adjust the Total Alkalinity first, then address the pH.

Cloudy waterPoor chemical control,  inadequate filtration or contaminants in the water. 

1. Clean or replace filter cartridge.

2. Check chemical levels and adjust if necessary (chlorine/PH).

3. Use a Pool Clarifier to remove small particles.

4. Shock Dose.

If the problem persists:

5. Empty the pool and re-fill with fresh water.

Rough pool sides / edgesScale formation due to high calcium levels in water1. Ensure PH levels are correct using Dip Test Strips.

2. use a Pool Scale Controller to stop calcium precipitating.

3. Clear and clean debris screens, pipework and check pool filter for build up. You may need to descale the filter pump as well.
No colour change on test strip dip testChlorine is too high and possibly bleaching of indicator pads (over 15ppm chlorine)Check the expiry date on Pool Test Strips. Wait for chlorine level to drop and re-test.

Check for faulty or counterfeit test strips.
FoamingDetergent, cosmetic products or excessive algaecide useUse Clearwater Foam Remover.


  • Do not leave non swimmers / children unattended
  • Do not overload the pool
  • Avoid sitting on pool walls
  • Do not allow diving in shallow water
  • Do not use during thunderstorms
  • Do not use electrical appliances near water
  • Use plastic rather than glass around the pool
  • Have a First Aid Kit available for any accidents


  • Read instructions thoroughly on each product/box before use.
  • When pre-dissolving chemicals, always add chemicals to water and not vice versa.
  • Never mix different chemicals in concentrated forms. This includes kit products but also with other chemicals like bleach or weedkillers – a dangerous reaction may occur.
  • Always pre-dissolve chemicals in a clean, plastic container in a well-ventilated area.
  • Avoid spillages. In the event of spillage, clean up using clean receptacles and dispose of them carefully.
  • Store chemicals in original packaging and never use unlabelled chemicals
  • Wash hands after handling pool chemicals


  • Store chemicals well away from children and pets
  • Store in a secure, cool and dry place


After the pool has been set up:

As soon as the pool is filled with water, you need to apply a booster / commissioning (Shock Dose) of Stabilised Chlorine Granules. Shock dosing a pool eliminates bacteria and any other contaminants in order to make it a safe swimming environment.

The amount of chlorine required to shock dose your pool depends on the volume of water. Refer to the instructions and guidance on your chemical packaging for dosage.

Top Tip: a tablespoon holds approx. 15g of Stabilised Chlorine Granules.

Rough Guide: You need 50gms of chlorine granules for a pool of 1000 gallons (4545 litres).

The importance of circulation and filtration:

It is a combination of circulating water and the filter cartridge collecting debris along with good chemical water treatment that helps you maintain clear, clean and healthy pool water.

You should run your pool's circulation every day referring to your user manual for more detailed advice. As a guide to running circulation, you should aim to "turn” the full volume of pool water through the filter cartridge once per day. Typically in most splash pools, using standard equipment, this is 4 hours per day (that the pump should be turned on).

Water testing and ideal pool chemical levels:

Using ClearWater Dip Tests you are able to quickly and accurately assess the condition of your pool water and make adjustments to chemical levels with the appropriate chemicals when necessary. Test daily when the pool is in use and twice weekly when the pool is not is use.
Free Chlorine1 - 3 ppm**ppm = parts per million
pH7.2 - 7.6 
Total Alkalinity80 - 120 ppm**ppm = parts per million




By regularly testing the pool water you will soon learn how various activities like refilling, topping up, adding chemicals and general usage can affect various test readings.



Pool Chlorine Maintenance:

ClearWater Stabilised Chlorine Granules are used regularly to disinfect the pool water and keep it free from bacteria, some of which may be hazardous to health. ClearWater's Chlorine Granules are quick-dissolving and relatively pH neutral. You simply measure out the quantity you need your pool's volume of water, dissolve in a jug of water and pour into the pool.

Quantity needed to increase pool chlorine level by just 1ppm :
1000 Gallons (4,545 Litres)9 Grams
2500 Gallons (11,364 Litres)23 Grams

Water should be tested before use and Free Chlorine levels should be 1 - 3ppm (parts per million). When adding chlorine to the pool, we recommend aiming for 3 ppm to provide a useful "buffer” for fluctuating conditions such as bathing loads and hot weather. The rate of chlorine consumption can and does vary depending on different conditions and chlorine will be consumed even when there is no swimming (i.e. by sunlight or by algae). The only way to be sure that there is sufficient chlorine present in the pool water is to test regularly.

Adjusting Pool pH Levels

The pH level of your pool water is also important as it helps to ensure the pool water is comfortable for bathers and the water is neither too acidic or alkaline. The ideal pH range for a pool is 7.2-7.6

  • Pool water with a pH below 7 is acidic which can cause unpleasant smells, bather discomfort and corrode metals. Use ClearWater pH Plus to reduce it using the application instructions on the bottle.
  • Pool water with a pH above 7 is alkaline which can cause skin irritation, scale formation and reduce chlorine efficiency. Use ClearWater pH Minus to increase it using the application instructions on the bottle.



Skin / eye irritation

Scale formation

Reduces chlorine effectiveness

7.2 - 7.6IDEAL LEVEL



Plant corrosion especially metals

Unpleasant smells and bather discomfort

Chlorine quickly used up











Algae are microscopic forms of plant life that can quickly multiply in ineffectively treated water conditions resulting in slippery sides and green or cloudy water. Chlorine used in pools helps prevent algae, but extra protection using ClearWater Algaecide really is both prudent and cost-effective. 

1000 gallons (4,545 litres)



2500 gallons (11,364 litres)







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Periodic cleaning of the waterline, steps and pool equipment will not only make your pool look good but it will optimise the use of your chemicals during a swimming season.

Use a skimmer or net to collect any debris floating on the surface. It is a good idea to do this on a regular basis to prevent any debris from causing contamination to the water. 

We recommend the Miracle Pads for general surface cleaning and the Scale & Stain Controller to help combat any tough stains. Avoid household cleaning products as they may contain phosphates that nurture algae growth or detergents which cause foam.


Working out pool water volumes can be tricky when considering how much of the pool chemicals you need to add. On most pool instructions the typical measurement will be provided in US gallons. See the table below for a typical guide:

10 ft diameter x 30 inches deep

800 UK Gallons (961 US Gallons)

3639 Litres

12 ft diameter x 30 inches deep

1183 UK Gallons (1421 US Gallons)

5377 Litres

15 ft diameter x 36 inches deep2240 UK gallons(2689 US gallons)10,179 Litres
15 ft diameter x 42 inches deep2720 UK gallons(3266 US gallons)12,362 Litres
15 ft diameter x 48 inches deep3038 UK gallons(3648 US gallons)13,807 Litres
18 ft diameter x 42 inches deep4203 UK gallons(5046 US gallons)19,100 Litres
18 ft diameter x 48 inches deep4661 UK gallons(5596 US gallons)21,182 Litres

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A quick guide to products needed for pool treatment:


1 - 3 ppm (aim for 3)ClearWater Stabilised Chlorine Granules

Daily when pool in use to maintain ideal levels

pH7.2 - 7.6

ClearWater pH Minus to reduce

ClearWater pH Plus to increase

Weekly or as required to maintain ideal levels

Prevent Algae

n/aClearWater Algaecide


See our full range of Pool Chemicals