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Disinfection systems     

CONTENTS: Links to sections

Ioniser disinfection
Saltwater chlorination
UV water disinfection
Ozone disinfection
Hybrid systems
Products

Introduction

In the interests of company policy of only marketing products that have been fully tested by ourselves before inclusion into our catalogue, we generally describe all the pros and cons of all the available disinfection systems we sell and distribute.

Customers can then make an informed decision based on environment, price, running costs, simplicity of installation and operation, and availability of parts and service.

Pool disinfection systems are designed to destroy bacteria, algae and animal pests such as lice, bugs, mites. Several methods are available. We describe here electro-mechanical equipment. For other chemical solutions please see our chemistry documentation.

Ionizers

A natural and effective disinfection system for pools. Now the least expensive, most cost effective, and easiest to install method of disinfecting a pool. Due to the increasing prices of chlorine and its availability, the problems of logistics for obtaining salt for salt water chlorinators, and the high cost of replacement cells, high quality ionizers are now available at highly competitive prices. The new generation of ClearBlue ionizers made in Canada provides an almost chlorine-free environment. They do not add any corrosive products to the pool that can damage metal fixtures and fittings. Ionizers are very easy to install and require no maintenance. ClearBlue electrodes are inexpensive and can be easily changed in one minute; they last for around 10 - 15 months under normal use. For small pools up to about 100m3, an ionizer can be used as a stand-alone solution, but they are also an ideal complement to existing UV and salt water systems.

Advantages and User Benefits

• Low purchase price, less than a replacement chlorinator cell of comparable performance
• Extremely low power consumption (about 7W)
• Crystal clear disinfected water
• Protection against 99.9% chlorine-resistant microorganisms and algae
• No chemicals added to the water
• Very easy DIY installation in 30 minutes
• Space-saving - no bypass or additional valves
• No health hazards whatsoever. Environmentally friendly
• Maintenance-free - 'set-and-forget'. No electrode cleaning required
• Easy 2-minute electrode replacement
• Inexpensive electrodes
• Electrode state is clearly visible at all times

For best results when using a saltwater chlorinator, you may wish to change the sand in your filter for glass filter media. ClearBlue is ideal for use with cartridge filters.

Downsides

• Like all 'chlorine-free' systems, the pool water needs the occasional addition of a small quantity of pool chlorine or a chlorine tablet.
• Occasional testing of the copper level (test strips supplied with ClearBlue ionisers)

How it works

A very low voltage current is supplied to an electrode. The electrode is a solid piece of metal, an alloy of silver, copper, and zinc. This self-sacrificial electrode releases ions of these natural elements into the water.

The disinfection properties of silver and copper have been known since ancient civilisations. They found that water in silver pots stayed purified, and algae didn’t grow in copper water containers. The hulls below the waterline of wooden sailing ships were clad with copper to resist the growth of algae and barnicles, hence the expression 'copper bottomed' for quality. NASA uses ionization for purifying the drinking water in space stations. There is also good reason that people are asked to throw coins in fountains and wells. Was it for good luck? Or was it the fact that the silver and copper in the coins actually purified and kept the water clean?

Mechanism of Action

In hospitals, copper-silver ionization is applied successfully for the deactivation of Legionella bacteria; wound dressings are impregnated with silver for its powerful disinfecting properties. Silver and most silver compounds have an oligodynamic effect and are toxic for bacteria, algae, and fungi in vitro. The antibacterial action of silver is dependent on the silver ion. The effectiveness of silver compounds as an antiseptic is based on the ability of the biologically active silver ion (Ag+
) to irreversibly damage key enzyme systems in the cell membranes of pathogens.

The antibacterial action of silver has long been known to be enhanced by the presence of an electric field. Applying an electric current across silver electrodes enhances antibiotic action at the anode, due to the release of silver into the bacterial culture. The antibacterial action of electrodes with silver nanostructures is greatly improved in the presence of an electric field..

Read more about ClearBlue ionisers here.

Salt Water Chlorinated Pools

Saltwater pools are not chlorine-free, nor are they chemical-free. A salt water pool is a highly chlorinated pool, simply with an alternative delivery system: salt water pools produce chlorine (hypochlorous acid) by flowing salt water through electrically charged titanium plates, called the salt cell. This process is called hydrolysis.

When the chlorine is used up, it converts back to NaCl, and the process continues.

A salt water pool is not better than a chlorine pool. Because when used with a saltwater chlorinator it is a chlorine pool. The chlorine that destroys bacteria, germs, and some algae is the same hypochlorous acid released by tablets, liquid or granular chlorine for pools.

User Benefits

• Salt costs only a fraction of the price of pool chlorine. Salt water pools are easier to maintain. Once set up, dosing is semi-automatic and reasonably accurate; there is little or no chlorine smell and unless bathers are particularly allergic to chlorine, they will not suffer from itchy skin or red eyes.

• Based on the sudden high cost of chlorine for pools (nearly doubling by mid 2022), a return on investment (ROI) can begin as soon as 18 months or so after installation.

• Salt water pools contain less than 10 times the salt in the sea, which has around 35,000 ppm of salinity. Salt water pools contain about 3000 to 4000ppm of salt dissolved in the water. The salt is imperceptible even if some people or pool merchants claim that it lends the water 'softer' or 'silkier' qualities.

Disadvantages

• Salt is lost through splash out, backwashing, and rinsing. Salt is not expensive but the cost if transport is very high. For pool owners living far from a pool shop, the cost of buying salt online is high, very high. It is recommended to keep a 6-month supply of salt in stock. Specially refined salt for pools comes in 25Kg blue-white bags and needs space for storage. Never use food grade salt in the red or orange bags, it will damage the chlorinator.

• Many pool builders construct pools for their clients in remote areas without realising that when it's needed, the weight of the salt costs more to transport than the price of the product in the bag. Before you opt for a salt water chlorinator, check out the availability of pool salt in your area. Otherwise when in town, load your pick up up with 20 - 30 bags. (or opt for an ionizer system instead)

• When filtering regularly during daylight hours, expensive Cyanuric Acid should be added to the pool water, but too much CYA will block the chlorine's disinfecting (oxidising) properties.

• High power consumption (depending on brand or model, often 400 - 500W or more for 6 to 8 hours a day)

• Saltwater systems do not measure the salinity in the pool and therefore does not proportionately dose the pool with its chlorine. You will need to  regularly check the salt level using a digital salinity meter (not a cheap TDS meter).

• A saltwater chlorinator represents an important investment. Calcium sediment (limescale) should be regularly flushed out of the cell with acid, often as frequently as every six months.

• The lifetime of a cell electrode can be up to 3 years if used correctly. Replacement cell electrodes are expensive and often cost around 70% of the price of the complete system. Check out the prices of cells before investing in a system. In some cheaper systems that have with the electronic controls integrated in the cell housing, the cell electrode cannot be replaced. The entire unit must be discarded and replaced.

• The chlorine level must nevertheless be regularly checked and the control unit adjusted if required.

How much salt does a pool need

Normally between 3kg and 5kg of salt for every 1,000 litres (m3) of swimming pool volume is required to reach 3,000 to 4,000 ppm. So you would need about 9 x 25 Kg bags to start a typical 10 x 4 pool. Different chlorinators require slightly different levels of salinity so do follow the manufacturers' recommendation for best results. Salt levels should be checked regularly. This can only be done using a digital salt meter (not a cheap TDS meter which only measures suspended solids). Higher quality salt water chlorinators display a warning when salt is low, some will emit an audible signal.

Cost of running a salt water chlorinated pool

Salt works out very much cheaper than buying chlorine products. Energy consumption is negligible. The cost of a chlorine generator varies by the size of the unit. High quality Chlorine Generators for pools from reputable brands start at around ฿30,000.00 for a small dip pool. Units with more sophisticated features can cost a lot more. Return on Investment: 1.5 to 2 years.

POOL SALT

Pool salt does not get used up. After producing chlorine it breaks back down to salt (sodium chloride). However, it does get lost through splash out, backwashing, and dilution from rain water. Salt for use with salt water chlorination systems is only produced by the TRS salt mine in Thailand:
• Specially prepared by TRS for swimming pools and spas.
• Contains no additives used in food grade or industrial salt
• High quality naturally mined salt, clean, very low levels of insoluble solids.
• Fine salt crystals, easy to pour, fast dissolving.
• Use only pool salt in the blue bag. The additives in household or food quality salt in the red back will shorten the life of the cell.Specially prepared for swimming pools and spas.
• Contains no additives used in food grade salt
• High quality naturally mined salt, clean, white, very low levels of insoluble solids.
• Fine salt crystals, easy to pour, fast dissolving.

Filter media

For best results when using a saltwater chlorinator, you may wish to change the sand in your filter for Zelbrite™ filter media.

Other chemicals

It is essential to maintain the pH between 7.2 and 7.6 for chlorine to work. Just as with manual chlorination, other pool chemicals, such as pH Minus or pH Plus, will still be needed. Algicides may also be needed even when using a salt chlorine generator.

UV (ultra-violet) disinfection

Medium pressure lamp ultra violet (UV) light systems reduce chloramine concentrations significantly. Recent evidence suggests that UV light systems, besides providing additional disinfection, also destroy chlorine resistant micro-organisms such as the parasitic protozoans Cryptosporidium parvum and Giardia lamblia.
The Emaux Nano Tech series of ultraviolet units are applied in the water treatment sector (residual and drinking water) as well as in swimming pools and ponds installations. These Emaux UV systems, which have since been copied by many manufacturers, are much more economical to buy and use than saltwater systems.

Advantages and User Benefits

• Crystal clear disinfected water
• Protects your pool against pathogenic organism and algae
• 316L corrosion resistant stainless steel housing, with mirror polished interior
• Environmentally friendly - injects no chemicals into the water
• Lamp lifetime approx. 9,000 hrs - medium cost of lamp replacementCrystal clear disinfected water

• Protects your pool against pathogenic organism and algae

• 316L corrosion resistant stainless steel housing, with mirror polished interior

Downsides

• DIY installation possible but not recommended. Needs bypass and extra valves
• Cumbersome lamp replacement
• Like all 'chlorine-free' systems, the pool water needs the occasional addition of a small quantity of pool chlorine or a chlorine tablet. (0.5 - 1.ppm)DIY installation possible but not recommended. Needs bypass and extra valves

How it works

The UV lamp provides a UV dose of 30mJ/cm2, which is sufficient for disinfection of the water and protection against 99.9% chlorine-resistant microorganisms.

UVC light at a particular wavelength 253.7 nm is a very powerful germicide. It deactivates the DNA of bacteria, virus and other pathogens and thus destroys their ability to multiply and cause disease.

Ultraviolet technology is a non-chemical approach to disinfection. In this method of disinfection, nothing is added which makes this process simple, inexpensive and requires very low maintenance.

UVC light is becoming increasingly favored by the pool industry for its ability to break down and remove the chloramines, which cause eye, skin and nose irritation, and breathing difficulties.

The UV lamp provides a UV dose of 30 mJ/cm2, which is sufficient for disinfection of the water and protection against 99.9% chlorine resistant micro-organisms.

Ozone disinfection systems

Nature’s most powerful sanitiser, Ozone effectively neutralises any organic contaminant instantly and reverts back to oxygen. Reduces the use of chlorine by up to 80% or more. Ozone may be used to control chloramines and has good disinfection properties. Low dose ozone (up to 2g/hour) is pumped with air through a venturi into a mixing chamber and reaction vessel in the circulation system after the pool water has been filtered. Provided the ozone is thoroughly mixed and dissolved, it reacts rapidly to destroy chloramines and disinfection by-products to reduce tastes, odours and eye stinging compounds.

The ozone produced by a corona discharge lamp is introduced into the water stream by Venturi effect.
Finally, the ozone and the ultraviolet radiation will work together to destroy micro-organism such as moulds, Legionella bacteria, parasites, algae or viruses, and also breaks down urine, transpiration, cosmetics and sun cream particles without leaving any by-products

Hybrid systems

The best of both worlds: Some disinfection systems include an attachment that additionally discharges ozone into the water.
Emaux has developed a special model of UV NanoTech which combines the ozone and UV-C technology in one unique equipment (see technical specifications for NT-UV87-TO).
Contains a high intensity Ultraviolet lamp different from the other UV models, this special lamp emits two separates wavelengths within the UV spectrum: 254 nm and 185 nm.
While the 254 nm wave deactivates the DNA of bacteria, viruses and other pathogens, the 185 nm wave is responsible for converting the oxygen contained in the quartz sleeve area into ozone.
Maytronics, the makers of the famous Dolphin pool cleaning robots, has teamed up with OzoneSwim of Australia to distribute a saltwater chlorinator with built-in ozone production.

Product links to our catalogue

Ionizers
Salt water chlorinators
UV systems
UV+Ozone
Chlorine+Ozone
Ioniser with chlorine production

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