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The Swimming Pool Operators

and Owners Resources Pages

Resource Page 2 - The Chemical Safety Page
  • WARNINGS.
  • Chemical Safety Issues.
  • Important Warnings.
  • Health & Safety Equipment (Personal Protection Equipment).
  • Choosing and Selecting the ideal chemicals for your pool.
  • Mixing and Hand Dosing.

DISCLAIMER:- All the information and advice on these web pages is given in good faith and believed correct and accurate, but we cannot be responsible for any form of loss, damage or injury, however caused, through the use of any information or advice detailed here.

COPYRIGHT:- All the information on these pages are for your PERSONAL USE. You may freely download, and retain anything that appears on this site provided you also retain and include a reference to this site and this copyright notice.. However, any part or whole of any article, text, or information that originates from this site may not be included in any publication, commercial literature, etc., etc., on any other web site, - or in any area where commercial or personal gain is conceived, without the express permission in writing from Malcolm R Bartier.

PLEASE NOTE:

  • We do not manufacture or distribute swimming pool chemicals and therefore have no loyalty to any particular brand or manufacturer.

  • We do not have any form of financial interest or reward from any chemical organisation, so you won't see any "recommended products" here.

  • We are not trying to persuade you to buy any particular brand of chemicals, and we will not specify or mention here any particular brand or manufacturer by name.

WARNING

Most Swimming Pool chemicals

can be HAZARDOUS

Too many chemical manufacturers and distributors give the impression that it is perfectly safe to "throw a handful" of something into your pool. They also sometimes suggest very exaggerated acceptable and safe levels levels for some chemical residuals.

We believe they do this to protect the sales of swimming pools, and the huge sales of pool chemicals, particularly to the home market. Perhaps it is thought that if prospective pool owners realized the hazardous nature of swimming pool chemicals, they would not consider buying a pool or the pool chemicals.

Although we ought to be able to trust chemical manufacturers and distributors to give us safe and correct, up-to-date information, it is a sad fact that sometimes some advice given by them is downright dangerous or hazardous.

Swimming Pool chemicals CAN be safely used -

PROVIDED you take the necessary PRECAUTIONS.

Treat ALL swimming pool chemicals with care and respect. Never take chances with safety

Remember, - Safety is No Accident!

It is essential that all chemicals are stored and administered in such a manner that the possibility of cross contamination by splashing or spillage is eliminated, and the opportunity for operator error is eliminated as far as is reasonably practical.

This means that each chemical is stored as far away as is reasonably practical from all other chemicals, in a clearly marked and defined area. Ideally, chlorine and acid are stored in separate rooms, each specifically designed to store chemicals, and with warning signs both on the doors and inside to remind operators which chemical is stored there.

Chlorine and Acid MUST be kept separate to avoid accidental mixing which will generat CHLORINE GAS.

Different types of chlorine MUST be kept separate to avoid accidental mixing which will cause FIRE, EXPLOSION or TOXIC FUMES.

 

HANDLING SAFETY POINTS

  • (1) ALWAYS wear a good pair of chemical-proof rubber gloves when handling any chemicals.

  • (2) ALWAYS wear splash proof goggles when handling exposed chemicals.

  • (3) ALWAYS wear a good quality dust mask when handling powdered chemicals.

  • (4) ALWAYS wear the correct respirator if handling chemicals that may fume or gas.

  • (5) ALWAYS wear a suitable protective apron to keep splashes and chemical dust off your clothes.

  • (6) ALWAYS ensure all children and other people are well away from you when you are handling or dosing chemicals.

  • (7) ALWAYS wash your hands after handling chemicals or chemical containers.

  • (8) ALWAYS allow at least 15 minutes for the chemicals to disperse before allowing anyone into the water.

  • (9) ALWAYS stand upwind if you have to throw chlorine granules directly into the pool.

  • (10) NEVER allow pool chemicals to come into contact with your skin.

  • (11) NEVER wear absorbant shoes (e.g. trainers) when handling liquid chemicals.

  • (12) NEVER wear trousers tucked INSIDE rubber boots - particularly if handling liquid chemicals.

  • (13) NEVER smoke, eat, or drink when handling or dosing chemicals.

  • (14) NEVER - NEVER - NEVER add chemicals to a pool whilst anyone is in the water.

 

Storage Safety Points

  • (1) NEVER store pool chemicals - particularly chlorine, near any gasoline, kerosene, oil, brake/hydraulic fluid, grease, oil-based paint etc.

  • (2) ALWAYS store Pool chemicals in a secure and safe place, and out of the reach of children.

  • (3) ALWAYS keep pool chemicals in a completely separate place to other stored items.

  • (4) ALWAYS store acid and chlorine separately so there is no possibility of each accidently coming in contact with the other.

  • (5) ALWAYS store pool chemicals in their original containers and in a cool, dark, dry place.

  • (6) ALWAYS make sure the relevant C.O.S.H. and/or Health & Safety Data Sheets are prominantly displayed.

 

IMPORTANT WARNINGS

  • (1) NEVER allow any type of chlorine to come into contact with any type of acid, except when in in the normal quantities found in pool water.

  • CHLORINE + ACID = CHLORINE GAS !!!

  • (2) NEVER allow two different types of chlorine to come into contact when in concentrated form. Fire, Explosion, or Toxic Fumes may result.

  • (3) NEVER, when mixing chemicals, add the water to the chemical. ALWAYS add the chemical to as large a quantity of water as possible. Water added to concentrated chemicals can produce violent reactions

  • (4) NEVER throw dry acid powder directly into the pool. It dissolves slowly and will quickly destroy grout between tiles, or cause "pickling" and damage to a vinyl liner. Mix Dry Acid thoroughly with water in a plastic pail until the solution is completely clear. Then pour carefully around the pool.

  • (5) NEVER pour acid down a skimmer. It will rapidly destroy the pool heater and any other metalic components, and may enter an Erosion Feeder and generate large quantities of Chlorine Gas.

  • (6) NEVER pour Chlorine granules or liquid down a skimmer if you have an erosion feeder installed. The chlorine will enter the erosion feeder and cause it to EXPLODE!!

  • (7) NEVER allow people to stay in the pool while you add chemicals. Commercial pools should have the pool hall or area completely cleared before any chemicals are hand dosed. Always allow time for the chemicals to mix and dilute before letting bathers return to the pool (suggested time - at least 15- 30minutes)

Health & Safety Equipment - also known as PPE - Personal Protection Equipment.

Commercial Pools have to observe a number of Safety Standards in order to satisfy Health & Safety requirements and legal obligations. In this section we are concerned with the handling of swimming pool chemicals.

In the UK it is a legal requirement that an employer provides adequate equipment to enable staff handle the various chemicals in as safe a manner as possible. It is also a requiremant that the staff use the equipment provided, and do not cause a danger to themselves or others by careless handling of these chemicals.

In addition to providing adequate and satisfactory PPE, the employer must ensure that employees are aware of the necessity to use this equipment. In some circumstances, this duty may be simply discharged by the use of warning signs and notices. Otherwise, training and familiarisation should be provided on a regular basis so that (A) the staff are made aware of the risks and dangers of handling chemicals, and (B) the staff are taught how to use the equipment in the correct and safe manner.

The following is considered the MINIMUM PPE equipment in the UK.

  • An eyewash station adjacent to each main chemical handling or decanting point.
  • A respirator capable of dealing with acid and chlorine gasses and vapours.
  • Chemical splash proof eye protection (ordinary spectacles are no protection)
  • Chemical resistant gloves or gauntlets
  • Chemical resistant apron
  • Chemical resistant and waterproof boots.

In addition

  • A full face mask respirator capable of dealing with acid and chlorine gasses and vapours may be preferable in some circumstances.
  • A good but simple disposable dust mask may be considered if only small amounts of chlorine granules are administered directly into the pool.
  • Chemical resistant arm protection (sleeves) should be used when decanting liquid chemicals.
  • Complete chemical resistant coveralls may be preferable especially when handling bulk liquid chemicals.
  • Footware should incorporate toe protection if cylinders are used for either CO2 or chlorine gas.
  • If chlorine gas is in use, self contained breathing sets must be provided and the staff trained to use them correctly & safely.
  • If chlorine gas is in use, a deluge type flood shower should be provided adjacent the gas cylinder connection area.
  • Comprehensive handling information (COSHH Data) for each chemical on the premises must be clearly visible at the storage point and at the handling point, and familiar to all staff likely to come into contact with those chemicals.

Warning signs

  • Sufficient warning signs must be clearly visible instructing staff that the various items of PPE must be used.
  • Each chemical storage tank and it's bund must be clearly labled to indicate the name and nature of the chemical stored.
  • The area set aside for chlorine storage must be clearly labled and marked, warning that no acids may be stored within that area.
  • The area set aside for acid storage must be clearly labled and marked, warning that no chlorine may be stored within that area.
  • Chemical dosing lines and pumps must be clearly marked and labled, indicating the particular chemical being administered.
  • Emergency Actions for a particular accident/incident must be clearly visible and easily understood.

It is difficult to provide a complete universal set or rules, guidelines and recommendations since each plantroom, each pool hall, and each chemical store is different.

We visit commercial (and some more enlightened private facilities) to determine any dangerous or unsafe working practises, and advise the best safety actions to impliment. We take into account the chemicals being used, the geography of the premises, and the local impact of any chemical accident or spillage.

We use our knowledge and experience to visualize potential accident situations, and then formulate the actions needed to minimize or eliminate the risk of those accidents occuring, and minimize or eliminate the health and safety risks to both staff and the public

Choosing and Selecting Swimming Pool Chemicals

The wide range of chemicals available for use in swimming pools is often bewildering to the new pool owner. All too often the pool installer will specify exactly the same chemicals that he has used on countless previous installations, only because he has never used anything else and is not familiar with the alternatives.

The two principle chemical groups are pH control and Disinfection. pH control can be subdivided into Acids and Alkalis. Disinfection can also be subdivided into Chlorine, Bromine, and Non Chemical Disinfection.

"Non Chemical" Disinfection

The term "Non Chemical" Disinfection" is rather misleading, since every disinfection process uses a chemical reaction at some stage. "Non Chemical", actually indicates that aggressive disinfecting chemicals are not regularly administered to the pool, and primary disinfection is achieved by other means - such as electronic - and secondary disinfection and oxidation is carried out on demand.

Residuals

With the exception of Chlorine Gas, swimming pool chemicals are not pure, they all are compounds of more than one chemical. This means that whilst part of the product will perform its task and be consumed, there will be a residual left in the water of an unused and undesirable chemical.

You CANNOT add another chemical to the water in order to remove the principle residuals. The ONLY way to control the build up of undesirable residuals is by dilution with fresh water.

To ensure economic and trouble free operation, it is important that the chemicals to be used in a particular pool are matched to the existing mains water supply. Nowadays, with fluctuating water supplies, it is important to regularly monitor incoming mains water to see if there has been such a significant change in the chemical-make that would prompt alternative swimming pool chemicals to be used.

There is no Ideal chemical, or group of chemicals for swimming pool use. Each available chemical has both advantages and disadvantages. These qualities will relate to ease of handling, dosing equipment required, their chemical residuals and the local mains water quality

When selecting chemicals for pool use, The installer or operator needs to take into account:-

  • (1) Make-up water residuals
  • (2) Chemical dosing and storage facilities
  • (3) Operator maintenance
  • (4) Health and Safety considerations.

For example, while an hotel pool would happily cope with a chlorine system which required cleaning once per week, this same system would not be suitable for a residential pool owner who does not wish to touch the equipment, or is away from home for long periods.

Available Popular Chemicals

pH Control - ACIDS

Dry Acid (Sodium Bisulphate or Sodium Hydrogen Sulphate) - Principle residual - Sulphates

Advantages - Easy to handle white crystalline powder. Does not fume. Available in small containers for residential pool owners. Reasonably safe while as a dry powder.

Disadvantages - Fairly slow acting. Leaves a residual of Sulphates in the water which, if allowed to accumulate, attacks grout, therefore extended regular pool dilution is required to control the sulphates level.. Must be thoroughly dissolved in water in a plastic pail etc. before adding to the pool, which can take several minutes.

Hydrochloric (Muriatic) Acid - Principle residual - Chlorides

Advantages. - Very fast acting pale yellow liquid. Has a low chlorides residual. Probably the cheapest acid available and widely used commercially.

Disadvantages - Normally sold at around 28% - 32% strength ( about 36% is usually the maximum possible). Produces highly irritating fumes above 20% strength. Must be diluted to about 8% for administering either by hand or through a chemical pump injection system. Usually available only in 25 litre containers or bulk Carboys.

Carbon Dioxide Gas - Principle residual - Bicarbonates

Advantages - A colourless, almost tasteless and odourless gas. Probably the safest method of pH control. Nothing to mix or spill. No corrosive fumes. Suitable for both residential and commercial use, ideal for Spas.

Disadvantages - Not a poisoness gas but it will displace oxygen causing asphyxiation. Impossible to Hand Dose. Additional dosing equipment essential. Can sometimes cause an increased Total Alkalinity level. Cannot be used to "shock down" Total Alkalinity.

pH Control - ALKALIS

Soda Ash (Sodium Carbonate) - Principle residual - Carbonates

Advantages - A fine granular white powder. Produces quick increase in pH value. Cheap.

Disadvantages - Excessive dosing can create cloudy water. Does not increase Total Alkalinity. Must be completely dissolved in water before use.

Sodium Bicarbonate - Principle residual - Bicarbonates

Advantages - A fine white powder. Increases both pH and especially, Total Alkalinity.

Disadvantages - must be carefully and completely dissolved in cold water before use.

CHLORINE DISINFECTION

Sodium Hypochlorite 10 - 15% available chlorine - Principle residual Sodium Chloride (salt).

Advantages - A pale yellow liquid (sometimes dyed purple). Creates an instant increase in chlorine levels. Good for shock-dosing. Not expensive

Disadvantages - Very highly corrosive and caustic, creating handling problems. Has a very short "Shelf-Life" - 4 months or less depending on storge method. Very high pH value, and adding to pool water causes a significant increase in pH value of pool water. Chlorine injectors may become easily clogged with Sodium Chloride compounds. Leaves a considerable level of Sodium and Chloride residuals, therefore extended regular pool dilution is required to control the sodium and chloride levels. Usually only available in 20 - 25 litre (5 gallon) containers or by bulk delivery tanker.

Dichlor Granules - 55% available Chlorine - Principle residual - Cyanuric Acid

Advantages - A fine white granular powder. Available in small quantities. Long "Shelf-Life". Designed for Hand-Dosing. Rapidly dissolves in pool water. Does not usually significantly affect pH levels

Disadvantages - leaves a very high residual of Cyanuric Acid, therefore extended regular pool dilution is required to control the Cyanurate level. Not suitable for Automatic Dosing. The dust is highly irritating to the respiratory system. Should never be used for Shock dosing. Should only be used for residential pools.

Calcium Hypochlorite - 65% available Chlorine - Principle residual - Calcium.

Advantages - A coarse granular white powder. Long "Shelf-Life". Fast acting chlorine compound. Can be used for Shock treatment. Does not contain Cyanuric acid.

Disadvantages - Chlorine injectors become easily clogged with calcium/chlorine deposits. Not really suitable for hand-dosing. Ideally requires mixing with water in a Day-Tank and injecting into circulation system using a chemical pump and injector. Needs addition of Cyanuric Acid if used in out door pool. The dust is highly irritating to the respiratory system.

Calcium Hypochlorite TABLETS - 65% available Chlorine - Principle residual - Calcium.

WARNING - WARNING - WARNING - WARNING - WARNING

  • This is a solid version of the calcium hypochlorite granules (above).
  • It is not to be confused with the Trichlor Tablets (below).
  • It must NEVER be placed in an ordinary trichlorinator/erosion feeder, as FIRE or EXPLOSION may result.
  • Some types of this tablet are designed for use in a special type of feeder, specifically manufactered to take calcium hypochlorite tablets
  • Read the manufacturers instructions carefully before using.

Trichlor Tablets - 90% available chlorine - Principle residual - Cyanuric Acid.

Advantages - White tablet. Requires an Erosion Feeder for dosing which is significantly smaller than a Day Tank containing a similar amount of chlorine. Long "Shelf-Life". Chlorine dosing points from the erosion feeder rarely, if ever clog. Does not contain high levels of Cyanuric Acid. Mixing or stirring chlorine solutions eliminated.

Disadvantages. - Should not be Hand-Dosed and only dosed via an Erosion Feeder. Very high chlorine content so Health & Safety equipment should be used while filling erosion feeder. Creates an acidic chlorine solution, so chemical for pH control may be either acids or alkalis, depending on make-up water content. Not suitable for shock-dosing.

Chlorine Gas - 100% available chlorine - Principle residual - Chlorine/Chlorides

Advantages - Greenish gas. Does not leave any other residuals in the water except chlorine (which eventually decomposes into chlorides). Highly acidic so soda ash is used for pH control instead of aggressive acids. Chlorine can be rapidly introduced into the water. Cost of chlorine is very inexpensive.

Disadvantages - Chlorine gas is a very dangerous gas. Expensive dosing equipment required to safely handle the gas. Expensive additional equipment required - eg self-contained breathing gear, gas alarms and flood showers to deal with gas leaks and contamination. Staff operating chlorine gas should be extensively trained and experienced to handle the gas equipment.

 

SPECIAL USE CHEMICALS

Sodium Thiosulphate (Chloriine Neutralizer) - Principle residuals - Sodium/Sulphates

Slightly acidic.

Coarse, glass-like crystaline granules, used for quickly destroying high levels of chlorine (or bromine). Dissolves easily in a bucket of water, and is administered directly evenly to the pool water. Will usually achieve about 75% destruction within an hour or so, but will continue to work for around 24 hours. Use with care, since it is easy to add too much - which then remains in the water to destroy additional chlorine subsequently added until the excess neutralizer is consumed.

Aluminium Sulphate (Alum) - Principle residuals - Sulphates & Aluminium (trace)

Acidic.

Either a course white crystaline granule, or solid lumps resembling "white coal" (Kibbled Alum). Used as a flocculant (filtration aid) to enhance the clarity of water by removing very fine particular suspension. Ideally dissolved into a 10% solution in water and slowly pumped into the circulation system before the filter. Correct dose is 2 ounces per square foot of filter area, and this amount in solution should be adminstered over 1 turnover period, AFTER backwashing the filter(s).

Filters must ALWAYS be backwashed before adding another dose of flocculant. Exceeding the recommended dose can cause filters to become clogged with alum.

Granular or Kibbled Alum should never be placed in the circulation pump strainer baskets as the water velocity is so high that it dissolves too quickly. The filter bed will not be correctly treated, the acidity can cause damage to heat exchangers in the circulation system, and cause chlorine gas to be generated if an erosion feeder is installed

The correct dose of Kibbled Alum may be placed in a skimmer basket, provided the flow is significantly reduced, AND an chlorine erosion feeder is not installed in the circulation system.

 

The process of selecting the Ideal Chemicals

Before you select the chemicals to be used at a particular site, make a note of the answers to all the following questions, and then apply them to each likely chemical in turn with respect to the properties listed above. You may wish to discuss this directly with your client so they can understand the reasoning behind your final judgment as to which chemicals you will be supplying.

pH Control

Carry out a make-up water test.

  • (1) What is the pH value?
  • (2) Are there significantly high levels of Sulphates present?
  • (3) What is the Total Alkalinity Level?

Assess the Users or operators of the system.

  • (4) Are they physically and intellectually capable of refilling or administering all, or only some of the pH control methods?
  • (5) How frequently will the Acid Storage need to be replenished?
  • (6) What are the possibilities of unauthorized persons entering the acid storage and dosing areas and causing damage or mischief.?
  • (7) Are there any other potential hazards which could compromise the safety of a particular pH control method?
  • (8) How similar, visually, is your chosen Acid to your chosen Chlorine, and how can mistaken identity be avoided?

Assess the Pool Installation

  • (9) Will the pool be in regular use, making hand-dosing difficult or impossible
  • (10) Is replacement water freely available?
  • (11) Is backwashing and water dilution easy, or are there restrictions on quantity or chemical content?
  • (12) Will the pool shell or equipment be damaged if specific residuals were not controlled?
  • (13) Will the use of the pool require heavy and regular dosing, or light and occasional dosing?
  • (14) Will the chemical control be Hand-Dosing, or will an Automatic Chemical Controller be used?

Chlorine Disinfection

Carry out a make-up water test.

  • What is the pH value?
  • Is there a significantly high or low level of Calcium present?
  • Is there a significantly high or low Total Alkalinity present?
  • Is there a significantly high Sulphates level present?

Assess the Users or operators of the system.

  • Are they physically and intellectually capable of refilling or administering all, or only some of the Chlorine control methods?
  • How frequently will the Chlorine Storage need to be replenished?
  • What are the possibilities of unauthorized persons entering the Chlorine storage and dosing areas and causing damage or mischief.?
  • Are there any other potential hazards which could compromise the safety of a particular Chlorine control method?
  • How similar, visually, is your chosen Chlorine to your chosen Acid, and how can mistaken identity be avoided.

Assess the Pool Installation

  • Is the pool located indoors or outdoors?
  • Will the pool be in regular use, making hand-dosing difficult or impossible?
  • Is replacement water freely available?
  • Is backwashing and water dilution easy, or are there restrictions on quantity or chemical content?
  • Will the pool shell or equipment be damaged if specific residuals were not controlled?
  • Will the use of the pool require heavy and regular dosing, or light and occasional dosing?
  • Will the chemical control be Hand-Dosing, or will an Automatic Chemical Controller be used?

The process of selecting the ideal method of administering chemicals.

Selection Procedure

  • Select the particular chemicals that have residuals that are a particular requirement - ie soft water areas with a low calcium hardness and a low total alkalinity usually benefit from Calcium Hypochlorite disinfection and CO2 gas for pH control.
  • Avoid using chemicals which will add further to an existing high residual - eg if the tap water already contains a high level of sulphates then avoid using Sodium Bisulphate (Dry Acid) for pH control.
  • Try to avoid using sodium hypochlorite (very highly alkaline) and dry acid for pH control - high levels of sulphates will be rapidly formed because the highly alkaline chlorine will cause a considerable amount of acid to be used.
  • Avoid using CO2 for pH control where the tap water has a Total Alkalinity in excess of about 120 ppm
  • Consider the handling implications - ie NO liquid chemicals must be carried in such a way that an accidental spillage causes a dangerous incident.
  • After initially selecting a group of chemicals, go through the lists above again and make sure you have made the best choice for the existing conditions.
  • Be prepared to revise you choice of chemicals if there is a significant change in the existing conditions.

Dosing Chlorine By Hand

  • (1) Is the pool indoors or outdoors?
  • (2) Will the pool be subjected to a high bather load?
  • (3) Is the pool expected to be used continuously or only occasionally for short periods?
  • (4) How much chlorine is expected to be used on a daily basis?
  • (5) What are the Health & Safety implications with respect to handling the expected amount of chlorine?
  • (6) What are the Health & Safety implications with respect to the storage of a sufficient amount of chlorine?
  • (7) Will it be possible to handle the chlorine at the expected dosing frequencies.?
  • (8) Do those persons who would be expected to handle the chlorine have the intellectual and physical ability to handle it as safely as possible?
  • (9) Do those persons who would be expected to handle the chlorine, have any reservations regarding the handling of chlorine?
  • (10) Will it be practically possible to maintain the correct level of chlorine on a continuous basis?
  • (11) What are the implications regarding use, if sufficient chlorine was not administered for any reason?
  • (12) Is it likely that the pool may be left unattended for a number of days at a time?

Dosing Chlorine using an Erosion Feeder

  • (1) Is it possible to install a suitable erosion feeder on the system?
  • (2) Can the erosion feeder be installed in a safe and easily accessible position for refilling and maintenance?
  • (3) Will there be any detrimental effect on equipment downstream of the erosion feeder?
  • (4) What are the Health & Safety implications with respect to handling the expected amount of chlorine?
  • (5) Will it be practically possible to refill the erosion feeder at the expected frequencies.?
  • (6) Do those persons who would be expected to refill the erosion feeder have the intellectual and physical ability to do this as safely as possible?
  • (7) Do those persons who would be expected to refill the erosion feeder, have any reservations regarding this action?
  • (8) Will it be practically possible to maintain the correct level of chlorine on a continuous basis by manually adjusting the erosion feeder control valves?
  • (9) Is there a possibility of an other type of chlorine entering the system either deliberately or accidentally, and entering the erosion feeder and so cause an explosion?

Mixing and Hand Dosing

Dosing using a Chemical Pump and Injector

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