Hot Tub Chemicals Guide

Explore our Hot Tub Chemicals Guide and find out everything you need to know from recommended chemical dosage amounts to chemical how-to guides.

We recommend ClearWater® chemicals as they are continuously designed for and tested on Lay-Z-Spa® hot tubs. All dosage and application recommendations below are based on ClearWater® hot tub chemicals and you should always refer to instructions and warnings included with each product before using.

Hot Tub Chemicals Quick Start Guide

Setting up your Lay-Z-Spa for the first time? Get started with hot tub chemicals in just three easy steps.

1. Shock Dose - Add Commissioning or Normal Shock Dose of Chlorine

After filling with water and before using your hot tub for the first time, shock dosing your Lay-Z-Spa is necessary to eliminate any bacteria or harmful organisms. It will also help to extend the time until you have to replace the water (assuming you keep up with regular chemical maintenance). Find out how to shock dose your hot tub in our Shock Dosing How-to Guide below.

2. Test Water After 24 Hours

After a commissioning shock dose, you need to wait around 24 hours. 

Test the water using the ClearWater Test Strips to make sure Free Chlorine, pH and Total Alkalinity levels are balanced before using the hot tub.

This may require you to adjust your pH, Alkaline and Chlorine levels. Dosage amounts will vary.

3. Start Your Regular Hot Tub Chemical Regime

In order to maintain clear, clean and healthy hot tub water there are some Daily, Weekly and Monthly Chemical Tasks that you will need to undertake.

The simplest way to do this is to always test the water before using your hot tub and make any adjustments to chemical levels as is necessary.

Chemicals Quick Start Guide
Lay-Z-Spa Chemical Care

Daily, Weekly & Monthly Chemical Care

Our recommended daily, weekly, monthly and ad-hoc hot tub chemical duties and caring information.

1. Keep Your Lay-Z-Spa Filter on

We recommend that the hot tub water should be filtered for a minimum of 4 hours a day. By leaving your hot tub on, the filter cartridge will collect suspended dirt and oils.

2. Test Chemical Levels before use
Always make sure hot tub chemicals are balanced to maintain clean and healthy water. If your chlorine, alkalinity or pH levels are not correct, please refer to our chemical How To guides below

3. Check Filter Cartridge

Ideally, filter cartridges should be removed and cleaned after every use. Every few weeks, or after periods of heavy use, Lay-Z-Spa Filters should be replaced with new ones. Look for discolouration or stiffness. 

How to clean your hot tub filter:

1. Ensure your pump is switched off.
2. Remove the complete filter housing from your Lay-Z-Spa.
3. Unscrew the filter housing and remove the cartridge.
4. Wash off the cartridge with a garden hose or cool tap water and leave to dry. Do not use any detergent or washing-up liquid to clean the filter.
5. Replace the filter with either a new or clean and dry one. Do not use a wet filter cartridge as this will not clean work effectively.

Every week there are a number of recommended activities you should carry out in order to prolong the life of your Lay-Z-Spa’s water.

Shock Dose If Used Frequently

Hot tubs are smaller than pools and are shared by more people, meaning a greater amount of contaminants are brought into the water. As a result, it’s recommended that you give a shock treatment to the water once a week during periods of heavy use. Find out how to do this in our Shock Dosing Guide below. During periods of less heavy use, the hot tub may not need to be shocked as regularly but keep an eye on water quality. Clear water doesn’t necessarily mean clean water.


ClearWater Clarifier contains flocculants that bind small particles of debris and algae together making it easier for your Lay-Z-Spa’s filtration system to capture and keep the water clear.

Every month you will need to carry out the following to maintain water hygiene:

Replace The Water

The frequency of water changes should reflect the degree of use of the hot tub, as well as the results of chemical testing. If chemical levels have fallen far outside the normal ranges, or if you experience a dramatic loss of water quality, it is recommended that the water is completely replaced and re-treated and tested again before use.

Some hot tub chemicals will need to be added depending on chemical reactions in the water.

Foam Remover

We always recommend that you shower before entering your hot tub. This is to reduce residue from products such as shampoo, deodorant, washing detergent, sun lotion, moisturiser, make-up, fake tan and natural body oils which can cause chemical imbalances. Despite showering we understand that these substances are still sometimes present and will react with the water resulting in foam being produced. In order to resolve, prevent and control this we would recommend that you add Clearwater Foam Remover to your Lay-Z-Spa.

Chemicals Dosages & How-To Guides

Get help with Shock Dosing your hot tub and advice on adjusting Chlorine, pH and Alkalinity levels.

Total Alkalinity (TA) is the measure of your hot tub water’s ability to neutralise acids. Balanced Total Alkalinity helps control the pH levels and the correct level to aim for is between 80 and 120 parts per million (ppm).

How To Balance Total Alkalinity Levels

1. Dip a ClearWater® Test Strip in the centre of your Lay-Z-Spa, remove and hold it still for 15 seconds. 

2. Compare your dip test strip results to the colour chart on the packaging.

3. Total Alkalinity results:

For low TA levels below 80ppm you will need to use Total Alkalinity Increaser. The amount of TA + you need to add to your hot tub depends on the volume of water and how low your readings are. As a guide - a hot tub of 1,000 litres requires 18g to raise Total Alkalinity levels by 10ppm (parts per million).

For high TA levels above 120ppm you will need to use PH Minus. The amount of pH decreaser you need to add to your hot tub depends on levels are and on the volume of water. Check the dosage rates on the back of the bottle and measure accordingly.

Problems Caused By Unbalanced Total Alkalinity Levels

Not balancing the Total Alkalinity levels in your hot tub can cause a number of issues that can impact your spa experience.

Scale build-up, cloudy water, clogged filters, weakened hardware and irregular pH levelsScale build-up, green water, irregular pH levels and loss of water quality
Burning eyes and itchy skinCorrosion of metal elements (i.e. pump)
Ineffective sanitiser Burning eyes and itchy skin

pH measures how acidic or alkaline your water is and the ideal range for 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 hot tub components and cause skin irritation.

How To Balance pH Levels in your hot tub

1. Dip a ClearWater® Test Strip in the centre of your Lay‑Z‑Spa, remove and hold it still for 15 seconds.

2. Compare your dip test strip results to the colour chart on the packaging.

3. pH results:

For low pH levels below 7.2 you will need to use pH Plus to help raise the pH levels and balance the water.

For high pH levels above 7.6, use pH Minus to help bring those levels back down into the recommended range

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

Problems Caused By Unbalanced pH Levels

Because pH measures how acidic or alkaline your water is, it is important to make sure your hot tub ph Levels are always balanced between 7.2 and 7.6 to avoid impacting your Lay-Z-Spa and your spa experience.

Skin and eye irritationDry, itchy skin and eye irritation
Cloudy or dull water and foamCorrosion of hot tubs components
Scale formationMore frequent filter changes
Less effective sanitiser (chlorine) Less effective sanitiser (chlorine)
Shorter filter runsImpact on Total Alkalinity

Chemical levels in your hot tub can be impacted by different causes and results vary with each situation. The number of bathers, water hardness and other outside materials such as mud, grass, and leaves will all affect chemical requirements. We would always advise you re-test the water before using your hot tub.

Chlorine is a sanitiser that controls and prevents bacteria growth and is essential for the hot tub water to be clean and safe to use. The recommended Free Chlorine* level in a hot tub is 3-5ppm (parts per million). 

How To Balance Chlorine Levels

1. Dip a ClearWater® Test Strip in the centre of your Lay‑Z‑Spa, remove and hold it still for 15 seconds.

2. Compare your chlorine results against the colour chart on the Dip Tests packaging.

3. Chlorine level results:

For low chlorine results below 3ppm you will need to add the appropriate amount of chlorine to restore the balance. Please see the instructions included on the Chlorine Granules or Multi-Function Chlorine Tablets packaging and view our Lay-Z-Spa Chlorine Dosage Recommendations table below. If the levels are very low we would suggest shock dosing the spa.

For high chlorine levels above 5ppm, we would suggest you drain the Lay-Z-Spa to the minimum mark and re-fill with fresh water to the maximum mark, this will help to dilute the excess chemical. Or, remove the cover from the hot tub to allow evaporation of the chemical (keep the spa filter running constantly).

Problems Caused By Unbalanced Chlorine Levels

It is important to get your hot tub Chlorine levels correct. Not enough Chlorine can result in unhygienic bathing conditions, whereas high Chlorine levels can cause irritated eyes or skin.

Poor sanitiser efficiency Poor sanitiser efficiency
Damage to componentsCloudy water
Red itchy eyes and skin rashBacteria Growth
Unpleasant smell

Lay-Z-Spa Chlorine Dosage Recommendations Table

Lay-Z-Spa ModelWater capacity in Litres
Grams based on 9g per 1000 litres

Teaspoons (one teaspoon = approx. 5g)
St Lucia AirJet
Aruba AirJet
Bali AirJet
Bahamas AirJet
Havana AirJet
Barbados AirJet
Tahiti AirJet
Cancun AirJet
Fiji AirJet
Madrid AirJet
Zurich AirJet
New York AirJet
Paris AirJet
Honolulu AirJet
Milan AirJet Plus
Palm Springs AirJet
Vegas AirJet84882
Miami AirJet80071
Ibiza AirJet77871
Hawaii AirJet84082
St Moritz AirJet
Santorini HydroJet Pro
Hollywood AirJet90882
Mauritius Airjet1370122
Grenada AirJet135012
Helsinki AirJet1123102
Hawaii HydroJet Pro
Majorca HydroJet Pro
Singapore AirJet Plus
Vancouver AirJet Plus
Maldives HydroJet Pro
Palma HydroJet Pro

Please note: The table is only applicable to Clearwater® Chemicals. Dosages are only approximate and the effect of chemicals on your water can vary each time you use them, depending on the exact amount of water in your hot tub, water type, water temperature, positioning of hot tub etc. Therefore it is essential to test the water every time before you use it.

*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.

Shock dosing a hot tub is adding a larger quantity of sanitiser, such as Chlorine, to break down organic matter, get rid of bacteria and any contaminants in the water making it safe to use. A shock dose can also help with any loss of water clarity or quality.

We recommend shocking your hot tub before first use, anytime the water is replaced, after periods of heavy use, at signs of slime or algae or after a loss of clarity or water quality.

How To Shock Dose Your Hot Tub

You need Chlorine Granules to shock dose a hot tub. Chlorine tablets are slow releasing and only used to maintain the correct daily chlorine level.

1. Check the water capacity of your hot tub and measure the Chlorine Granules accordingly. The size of your hot tub will impact how much chlorine you need to add. Use the shock dose recommendations table below to see how much chlorine you need to add to your Lay-Z-Spa.

2. Dissolve the quantity of Chlorine Granules in a jug of warm water and pour into your hot tub. Activate the AirJets for a few minutes to circulate the chemicals evenly throughout the water.

3. After shock dosing your hot tub, you will need to wait a minimum of 24 hours. Then, test the chlorine level with the dip test strips and make sure levels are 3-5ppm. Add more Chlorine if necessary and balance all chemicals before using the hot tub. 

Lay-Z-Spa Shock Dose Recommendations Table

Lay-Z-Spa ModelWater capacity in LitresGrams based on 20g per 1000 LitresTeaspoons (one teaspoon = approx. 5g)
St Lucia AirJet
Aruba AirJet
Bali AirJet
Bahamas AirJet
Havana AirJet
Barbados AirJet
Tahiti AirJet
Cancun AirJet
Fiji AirJet
Madrid AirJet
Zurich AirJet
New York AirJet
Paris AirJet
Honolulu AirJet
Milan AirJet Plus
Palm Springs AirJet
Vegas AirJet848173
Miami AirJet800163
Ibiza AirJet778164
Hawaii AirJet840174
St Moritz AirJet
Santorini HydroJet Pro
Hollywood AirJet908184
Mauritius Airjet1370275
Grenada AirJet1350275
Helsinki AirJet1123224
Hawaii HydroJet Pro
Majorca HydroJet Pro
Singapore AirJet Plus
Vancouver AirJet Plus
Maldives HydroJet Pro
Palma HydroJet Pro

Please note: The table is only applicable to Clearwater® Chemicals. Dosages are only approximate and the effect of chemicals on your water can vary each time you use them, depending on the exact amount of water in your hot tub, water type, water temperature, positioning of hot tub etc. Therefore it is essential to test the water every time before you use it.

When Do I Need To Shock Dose My Hot Tub?

· When you first fill up with water
· At the first signs of algae or slime
· After periods of heavy usage
· After a loss of water clarity or quality
· After a long period without use
· When you re-fill with fresh water

Can I Use Chlorine Tablets To Shock Dose My Hot Tub?

Tablets such as the Clearwater® Multi-Function Chlorine Tablets are only to be used for keeping your chlorine levels stable. Tablets are slow dissolving and will not have the same impact as granules. 

I have added An Initial Dose Of Stabilised Chlorine To My Lay-Z-Spa, When Can I Use It?

You can use your hot tub when the chlorine level sits between 3-5ppm. You should allow at least 24 hours for any treatment to the water to dissolve fully and be safe to use.

Lay-Z-Spa Chemical Dosage
Hot Tub Water Problem Solving

Water Problem-Solving Chart

Find out the causes and solutions to water issues your hot tub may be experiencing.

Water issues may seem like a difficult task to resolve, but by using our Water Problem Solving Chart below you can easily identify the causes and remedy.

Green / cloudy water / slippery sidesInadequate sanitiser. Algae may be presentShock dose with chlorine (see shock dose table) and add foam remover or clarifier.
Too much chlorineOverdose

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

2. Remove the cover from Lay-Z-Spa to allow evaporation of the chlorine (keep the filter running constantly).

PH hard to controlAlkalinity lowAdd Total Alkalinity Increaser – see packaging for dosage information
Can't maintain chlorine levelsChlorine demand of water too high at start up, after holidays or due to excess contamination or neglect

1. Shock dose with a double dose of chlorine.

2. Use the test strips to check chemical levels every day, the filter should be left on for a minimum of 4 hours a day when there is water in the hot tub.

3. If chlorine levels are fluctuating, you will need to check other chemical levels are correct. If the hot tub is being used quite a lot you may need to increase the chlorine levels.

4. If you are going away we would suggest emptying the hot tub and cleaning it so the water is not left to go stagnant. Do not re-fill until you return from your trip.

Cloudy waterPoor chemical control or inadequate filtration1. Clean or replace the filter cartridge

2. Test & adjust chemical levels

3. Use
 clarifier to remove small particles in the water

4. Shock dose the water

If problem persists:

5. Empty water, clean hot tub inside and out, backwash the pump, replace filters and re-fill with fresh water.
Rough pool sides / edgesScale formation due to high calcium levels in waterEnsure PH levels are correct using ClearWater Dip Test Strips.

If you live in a hard water area, use the Scale & Stain Controller frequently.

No colour change on test strip dip testToo high chlorine leading to bleaching of indicator pads (over 15ppm chlorine)Check the expiry date on ClearWater Dip 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.

Chemical Handling & Storage

Ensuring yours and others’ safety when handling chemicals is highly important as failure to do so could cause serious harm or a fatality. Please, therefore, read the below instructions carefully on how to correctly store and handle chemicals.

Read Instructions Thoroughly On Each Product Before Use

Never use unlabelled chemicals and please read the instructions before use. Avoid getting chemicals in eyes, on skin or on clothing. Avoid breathing vapours when opening a container. Avoid creation of dust. Never add water to the product. Always add product to large quantities of water. Use separate clean dry utensils for each chemical and clean after use. Do not add the product to any dispensing device containing residuals of other products.

Wear Protective Clothing

When you’re ready to begin mixing your chemicals, you should handle them with chemical resistant gloves. The glove material has to be impermeable and resistant to the product/ the substance/ the preparation. It is also advised to wear tightly sealed goggles and appropriate protective clothing such as long sleeves, trousers, and closed-toed shoes that fully protect your feet from spills. You should also wash your hands after handling chemicals.


Spillages & Disposal

In the event of spillage, clean up using clean receptacles and dispose of carefully. Do not add water to spilled materials. Do not use floor sweeping compounds to clean up spills. Sweep and scoop spilled material into clean, dedicated equipment.

Every attempt should be made to avoid mixing spilled material with other chemicals or debris when cleaning up. Do not attempt to reseal any contaminated drums. Do not transport wet or damp material.

Adding Or Pre-Dissolving Chemicals

Always pre-dissolve chemicals in a clean, plastic container in a well-ventilated area. When pre-dissolving chemicals always add chemicals to water and not vice versa. Always add the chemicals to the water.

Never mix different chemicals in concentrated forms. This includes the kit products but also with other products like bleach or weedkillers – a dangerous reaction may occur.


Do not eat, drink or smoke when using this product. Have a First Aid Kit available for any accidents

- If inhaled: Seek fresh air and keep at rest in a position comfortable for breathing.
- If in eyes: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing. If eye irritation persists: Get medical advice/attention.
- If swallowed: Get medical advice/attention or call a poison centre.

For general safety advice on using your Lay-Z-Spa or chemicals, please refer your manuals.

Safe Storage

Store in a secure, cool and dry place. Chemicals must be kept well away from children and pets. Always keep chemicals in original packaging.

Avoid Exposure to Sunlight and Humidity

When considering where to store your chemicals, the best storage locations are areas out of direct sunlight. Chemicals react poorly when in contact with sunshine and heat and require a dark, cool environment to control for any potential reactions.

Make sure that any outdoor storage of chemicals is as far away from your hot tub as possible and in a dry, covered area. Humidity or even small amounts of water can cause chemical reactions that could lead to dangerous fumes.

Provide Plenty of Ventilation

Choose a location with ample ventilation for storing your chemicals. In areas with little airflow, dangerous fumes can quickly accumulate if chemicals do start to react. Ventilation is even more important when multiple chemicals are stored in close proximity to each other, as certain chemicals may create a hazardous reaction when combined.

Be Attentive to How You Store Different Chemicals

Refrain from stacking different chemicals on top of each other as this is not advised. Storing chemicals requires careful attention to the product label instructions for each individual product. Material Data Safety Sheets (MSDS) are provided with each chemical product upon purchase and should be referenced with care. Keep in mind to never store oxidizers and acids close to each other.

Take care to never store any chemicals on the floor or above your head. This reduces the risk of items falling or spilling. In addition, avoid stacking liquid chemicals above powdered ones due to the risk of a hazardous reaction.

Keep Chemicals Away From Flammable Items

Outdoor storage areas for your hot tub chemicals should be situated away from anything flammable. Keep any petrol-powered equipment, like your lawnmower, in a different location. The storage area should also be away from sources of heat, like an outdoor fire pit or BBQ.

Do Not Reuse or Switch Container

Reusing chemical containers or transferring chemicals to another container is never recommended as it can be hazardous. When storing your chemicals, always use the original containers with their labels clearly legible. Each container was designed for the specific storage requirements of the chemical it contains.

Even if you’re handling the same type of chemical, mixing a new batch of a chemical with a leftover batch of the same chemical can lead to a reaction from the older residue, or create fumes.

Lay-Z-Spa Chemical Handling & Storage
inflatble Hot Tub Chemicals What Are They and What Do They Do?

Chemicals & What They Do

Explore this list ClearWater® chemicals including their key properties and uses.

ClearWater® is our chosen and recommended chemical provider. Developed with Lay-Z-Spa in mind, the range of ClearWater® hot tub chemicals includes everything needed to make sure your Lay-Z-Spa's water stays safe, clean and clear. Explore the table below which includes each product’s use and function.

Clearwater Chlorine GranulesGranulesClearwater Chlorine Granules are one of our most popular products and are considered an essential item in every hot tub owner’s tool kit. Chlorine granules disinfect the spa water by killing bacteria which builds up in your Lay-Z-Spa. They are quick dissolving and relatively pH neutral.
Clearwater Dip Test StripsStripClearwater Dip Test Strips are a quick, easy but essential way to check the chlorine, pH and alkalinity levels of your spa water, allowing you to provide it with the right treatment if necessary. Untested water can develop a chemical imbalance which may result in an unhygienic swimming environment or skin irritations. Simply dip a test strip into your hot tub water, quickly remove it and allow the colour to develop. The results can be checked against the colour chart provided, indicating each level.
Clearwater Mini Multifunction TabletsTabletClearwater Mini Multifunctional Tablets are an effective and hassle-free way of maintaining clear and healthy spa water. They contain a combination of chemicals that act in a number of ways. These slow-release tablets contain chlorine, algaecide and water clarifier. The chemical dispenser slowly releases the mini-tablets into the water, making this a completely hassle-free way of treating your water even for the user with a busy schedule.
5-inch Chemical FloaterChemical Tablet DispenserThe 5 Inch Chemical Floater slowly releases Clearwater Mini Multifunctional Tablets or Chlorine Tablets, making it the perfect accessory for busy spa users who want a hassle-free way of maintaining clear and healthy spa water. The dispenser has an adjustable dial which controls the release of the 20g tablets, ensuring that the sanitizer level of your spa water is consistently and efficiently maintained. Compatible with all spa models.
Clearwater pH PlusGranulesClearwater pH Plus, also known as ‘pH increaser’ is the best way to increase pH levels that have dropped below the recommended level. To avoid skin discomforts and enable the chlorine in your spa to work effectively, it’s vital that acidity is monitored and controlled. The recommended pH balance of spa water is between 7.2 and 7.6.
Clearwater pH MinusGranulesClearwater pH Minus, also known as ‘pH reducer’ is the most simple and effective way to decrease the pH of your spa water when it has surpassed the recommended level.
Clearwater ClarifierLiquidClearwater Clarifier contains flocculants which bind small particles of debris and algae together so that your Lay-Z-Spa filtration system can adequately remove them, resulting in clean and sparkly water. This is a very effective way of preventing your spa water from looking dull and cloudy, due to the build-up of dead algae and debris that is too small to be trapped by your filter. Even if you have treated your spa for algae using Clearwater Algaecide, it is recommended that you use the Water Clarifier to remove any residual debris.
Clearwater AlgaecideLiquidClearwater Algaecide is the quickest and most effective way to eliminate and prevent the build-up of algae, which provides an ideal breeding ground for germs and bacteria.
Clearwater Foam RemoverLiquidClearwater Foam Remover is designed to control and prevent foaming in your hot tub, which is typically caused by the reaction of water with shampoos, deodorants and natural body oils present on the user.
Scale and Stain RemoverLiquidClearwater Scale and Stain Remover is great for hard water areas.
Chem connectChemical tablet dispenserThe chem connect attaches to the top debris screen on the liner of the spa. It slowly releases clearwater tablets. The dispenser has an adjustable dial which can control the release. Please remove the chem connect when the spa is being used. Compatible with spas made in 2019 onwards.
Find Chemicals for Your Hot Tub

Looking for Chemicals?

We stock a wide range of ClearWater Chemicals all specially designed for use with Lay-Z-Spa hot tubs.

Hot Tub Advice

Need Advice on Hot Tub Maintenance?

Visit our Lay-Z-Spa FAQs and get advice on looking after your hot tub, chemical maintenance and more.

Lay-Z-Spa hot tub accessories

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