Pool Chemicals Guide

Shock dosing a pool is adding a larger quantity of sanitiser, such as Chlorine. This is to break down any organic matter, get rid of bacteria and any other contaminants in the water to make it safe to use.

A pool shock dose can also help with any loss of water clarity or quality.

Pool water needs a shock dose treatment:

• When you first set up and fill up with fresh water
• After periods of heavy usage
• After a long period of time without being used
• After a loss of water clarity or quality
• After refilling with fresh water

A pool shock needs Chlorine Granules. Chlorine tablets are slow-releasing and should only be used to maintain daily chlorine levels.

1. Check the water capacity of your pool and measure the correct amount of Chlorine Granules. The volume of water dictates how much chlorine you need to add.
   
2. Dissolve the correct amount of Chlorine Granules in a jug of warm water and pour directly into your pool near the filter inlet, with the filter on, so that it circulates the chemicals evenly throughout the water.
   
3. After shock dosing your pool, you need to wait a minimum of 24 hours. After 24H, test the chlorine level with the dip test strips and make sure levels are 1-3ppm. Add more Chlorine if necessary, but balance the pH and Total Alkalinity first. 

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.

Rough Guide:

• 50grams for a 5000 litre pool
• 100 grams for 10000 litre pool
• 150grams for a 15000 litre pool

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

Total Alkalinity (TA) is the measure of your pool water’s ability to neutralise acids. It acts as a buffer to neutralise pH.

If alkalinity is not balanced, pH levels can go up-and-down and chlorine levels are difficult to manage.

We always recommend balancing a pool's Total Alkalinity level before doing anything else.

Balanced Total Alkalinity helps control the pH levels of the pool's water. Together, these help maintain stable chlorine levels.

If either Total Alkalinity or pH levels are off, you may notice a drop in water quality, cloudy water, itchy skin, and it could become corrosive to internal parts such as the heater pump, pipes and even the liner.

The correct TA level to aim for in a pool is between 80 and 120 ppm (parts per million).

• For low TA levels below 80 ppm you should use an Alkalinity increaser. The amount of TA + you need to add to your pool depends on the volume of water and how low your readings are. As a guide, 1,000 litres of water requires 18g to raise Total Alkalinity levels by 10 ppm (parts per million).
  
• For high TA levels above 120ppm you need to use a PH reducer. The amount of pH reducer you need to add to your pool will depend on TA levels are and on your pool's volume of water. Check the dosage rates on the back of the bottle and measure accordingly.

Low Total Alkalinity:

• Unbalanced low pH levels
• Loss of water quality
• Skin and eye irritation
• Corrosion

High Total Alkalinity

• High pH levels
• Irregular Chlorine levels
• Cloudy, milky, foamy water
• Scale build-up

High TA can be caused by:

• Cosmetics, body lotions, perfume, make up etc
• Hard water
• Water has been in too long and TDS* is high (*Total Dissolved Solids)

Low TA can be caused by:

• Rainwater
• Organic contaminants brought into the water by users.

pH measures how acidic or alkaline your pool water is. The ideal range for pools and hot tubs is between 7.2 and 7.6.

Balanced pH is necessary for other chemicals to work properly and imbalanced pH levels can impact your pool components and cause skin irritation.

When testing your pool water, aim for a reading of 7.2 and 7.6

• Low pH levels below 7.2 need pH Plus to help raise the pH levels and balance the water.
  
• High pH levels above 7.6, need pH Minus to help bring those levels back down into the recommended range

The amount of pH increaser or reducer you need to add to your pool depends on the volume of water and how low your readings are. Refer to the dosage information printed on the individual chemical bottles.

Low pH:

• Less effective chlorine
• Loss of water quality
• Irritation to skin & eyes
• Corrosion

High pH

• Skin & eye irritation
• Chlorine levels fluctuating
• Cloudy, milky foamy water
• Scale build-up

Chlorine is a highly effective sanitiser that controls and prevents bacterial growth and is essential for the pool water to be clean and safe to use.

Without chlorine in a pool, the water will rapidly become cloudy, algae may start to form and could quickly become unpleasant or unhealthy for users.

The recommended Free Chlorine* level in a pool is 1-3 ppm (parts per million).

Click on the Chlorine dosage guide for recommended amounts.

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

*Free Chlorine refers to the amount of chlorine in your hot tub that is available to sanitise or disinfect the water, keeping it safe for users.

The rate of chlorine consumption depends on different individual circumstances, and chlorine will be consumed even when there is no swimming (i.e. by sunlight, contaminants or algae).

The only way to be sure that there is sufficient chlorine present in the pool water is to test regularly.

When pool chlorine falls below 1 ppm, bacteria and algae can start to grow, and water quality can drop quickly.

You will need to add the appropriate amount of chlorine to restore the balance.

Your options are:

• Chlorine granules - the most accurate way of raising chlorine levels in a short space of time, including a shock dose
• Chlorine tablets - these are slow release, so could take some time to raise Free Chlorine ppm if it is very low.
• Fast Action Tablets - these go straight into the water and a great for a quick boost of chlorine as they dissolve in 30 minutes.

Low chlorine levels:

• Loss of water quality
• Cloudy water
• Bacteria growth
• Bad smell
• Bio film

For high chlorine levels above 5ppm, we strongly recommend not using your pool as it could likely cause irritation.

We would suggest you drain some of the water from your pool and re‑fill with fresh water. This will help to dilute the excess chlorine.

High chlorine levels:

• Itchy skin & burning eyes
• Corrosive
• Discolouration

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 helps prevent algae in pools, but Algaecide is an algae killer and preventative that can be used in your pool water.

Once algae forms in a pool, it is important to address it quickly.

We recommend shocking the water, replacing the filter and using an initial booster dose of Clearwater® Algaecide.

Rough Booster Guide:

• 55ml for a 5000 litre pool
• 110ml for 10000 litre pool
• 156ml for a 15000 litre pool

Rough Weekly Guide:

• 28ml for a 5000 litre pool
• 55ml for 10000 litre pool
• 83ml for a 15000 litre pool

The best ways to prevent pool algae are:

1. Keep correct chlorine levels
2. Use a pool cover
3. Add a weekly does of Algaecide
   28ml for a 5000 litre pool
   55ml for 10000 litre pool
   83ml for a 15000 litre pool

Sanitising pool water is crucial to remove bacteria and contaminants. For this, we recommend Chlorine.

Balanced water chemistry takes into account the alkalinity and pH of your water, so you may require pH Minus, pH Plus and TA Plus.

Other pool chemicals are classed as non-essential but may be required in certain circumstances.

For beginners, we suggest getting the ClearWater® Pool Starter Kit. This includes the basics to get started and it might be all you need.

The short answer is no.

Factors such as heavy use, how clean the bather are and seasonal environment, some chemical levels may change more than others but it is generally a case of periodically making minor adjustments, such as adding some chlorine.

Our advice is to test the water a few hours before you want to use your hot tub and making necessary adjustments, if any are needed.

Scroll back up this page and you will find recommended dosage and advice for the essential pool chemicals.

All ClearWater® pool chemicals include dosage recommendations on the packaging.

After an initial shock dose, the correct order to manage and balance pool chemicals is:

1. Total Alkalinity (80‑120 ppm)
2. pH levels (7.2‑7.6)
3. Chlorine (1-3 ppm)

• 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.
• Wash hands after handling pool chemicals

• Store chemicals well away from children and pets
• Store in a secure, cool and dry place
• Store chemicals in original packaging and never use unlabelled chemicals