Comparison Between Saltwater pools vs Chlorine
With summer just around the corner and a “little” pressure from the family, you have finally got around to thinking about installing a swimming pool. Like most people, one of the questions raised is what type of pool do you install, saltwater pools vs chlorine or to add more confusion to your already confused mind alternates that use very little chlorine or none at all.
Hopefully after reading this post your questions are answered and any confusion you had is removed. Let’s start by comparing each type.
By far the most common home pool type is currently the saltwater pool.
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Salt Water Pools vs Chlorine
The similarities of Salt Water Pools and Chlorine Pools
It needs mentioning that both salt water and chlorine pools require chlorine to reduce bacteria, clean and sanitize the pool.
The difference is the methods applied to achieve it and the levels of chlorine produced.
Salt Water Pools
By definition the water in a salt water pool is obviously salty, why salt? In a saltwater pool, chlorine is produced by “electrolysis” which automatically converts the salt water into measured and safe levels of chlorine.
To achieve this, a salt water pool uses a device called a Chlorinator which is installed as part of the pools filtration system.
A positive benefit of saltwater pools is the lower and measured levels of chlorine produced by the automatic chlorinator.
Therefore, the lower levels of chlorine result in much less irritation to skin and eyes without effecting the cleaning and sanitizing process of the pool.
With a new pool it will be necessary to apply a few bags of salt to get the chlorination process happening, the quantities of salt required will be determined by size/water volume of your pool.
With a new pool this should be provided to you by the supplier/installer of your pool.
It will be necessary to add more salt to the pool from time to time, especially after periods of medium to heavy rain.
The effect of medium to high levels of fresh rainwater entering the pool will be the dilution of the salt levels which may affect the automatic chlorination process and therefore chlorine levels in the pool.
Adding salt to a pool is a simple and inexpensive process compared to adding chlorine.
The sides and bottom of the pool need regular cleaning. This is done either manually with a brush and net or made simple with use of an automatic pool cleaner.
The pool cleaner is connected by a long special purpose flexible hose to an attachment placed inside the skimmer box and controlled by the pool’s filtration system.
There are many pool cleaners available on the market and can be purchased from your local pool shop or on-line.
The skimmer box, pump filter and sand filter need to be checked and cleaned regularly. Depending on the pool’s environment, the skimmer box and pump filter should be checked and cleaned at least every other day.
Also, the sand filter needs to be back washed when suction pressure starts to fall off, this is a very simple process (refer to filter systems manual).
If the unit is working properly you will see a cloud effect swirling around in the water at either end of the chlorinator’s plates.
When you see a build-up of deposits on the chlorinator plates it is time to remove the chlorinator from its plumbing and follow the cleaning instructions.
Although a relatively simple process, it involves the use of diluted hydrochloric acid so care needs to be taken (follow the pool filter system manual).
To ensure your pool looks sparkling clean like those you see at hotels, most public pools and those you see in magazines and movies the addition of some selected pool safe chemicals can be applied.
Advantages of a Saltwater Pool
• Low and measured levels of chlorine.
• Less irritation to skin and eyes without effecting the cleaning and sanitizing process of the pool.
• Safer, as there is no handling and storage of chlorine
• Less chemicals required therefore lower cost
Disadvantages of a Saltwater Pool
• High purchase and installation costs
• Salt can cause some corrosion of metal parts and materials used for pool equipment
As mentioned above, both salt water and chlorine pools use chlorine to reduce bacteria, clean and sanitize the pool. The difference is the methods applied to achieve it and the levels of chlorine produced.
Unlike a Salt Water pool where the chlorine is produced automatically by a Chlorinator that converts salt water into measured and safe levels of chlorine, a Chlorine Pool requires measured quantities of Chlorine to be directly added to the pool manually (most common method).
The chlorine level is measured in parts per million (ppm) and needs to be between 1.0 and 3.0 ppm and measured by using a Pool Water Test Kit that measures both chlorine levels and pH levels.
The pH is a measure of the pool water’s acidity. The optimum pH for pool water is 7.4, the same as the pH in human eyes and mucous membranes. A pH of 7.4 also assist the chlorine’s role of reducing bacteria, cleaning and sanitizing the pool.
Advantages of a Chlorine Pool
• Lower purchase and installation cost
• Lower annual operating costs. This needs to be compared to cost of chlorine vs energy costs
• Only a circulating pump required
• Less damage to pool fixtures and fittings
• Largely DIY friendly
Disadvantages of a Chlorine Pool
• Chlorine and pH levels require checking more regularly.
• Potential for higher than safe levels of chlorine.
• Chlorine needs to be manually added to the pool
• Potential for higher levels of eye and skin irritation, due to higher levels of chlorine
• Higher pool water treatment costs
• Storage and handling of chlorine
Alternatives to Chlorine
The information provided above was to provide comparisons between Saltwater and Chlorine Pools. The common denominator for both types was Chlorine. Chlorine has been the most common and safe chemical used throughout the world for the treatment of swimming pool water, there are now alternatives to be considered
The main reason Chlorine has maintained its popularity is its relatively low cost and multifunction properties of cleaning, sanitizing, oxidization and the control of algae.
There are now alternatives to chlorine including Bromine, Ionizers, Ozonators and PHMB. However, they are all expensive and all but one still requires a small quantity of chlorine??
Although having less of an effect on people with an allergic reaction to chlorine, however, this is not guaranteed as Bromine comes from the same chemical family as chlorine.
Bromine is a very good sanitizer but does not have the oxidization properties as chlorine. It is these properties that control of organic materials caused by body perspiration and oils and the build-up of algae.
Due to Bromine’s low oxidisation properties a low level of chlorine needs to be applied.
The ionizer alternative is largely a nonchemical, electrical sanitization method using two dissimilar metal probes, usually copper and silver. The copper probe acts as an algaecide and the silver probe a sanitizer.
The two probes are connected to a low voltage DC source, this causes a positive charge to be created that attracts bacteria and organic materials plus reduces the level of algae.
However, the ionization method does not have the same oxidation process as chlorine therefore to have the same cleaning, sanitizing and oxidization benefits a relatively low level of chlorine or bromine will need to be added to the water.
This alternative is also a largely non chemical, sanitization method. There are two types of Ozonators one uses UV (ultra violet light) the other uses an Ozone generator.
The UV (Ultraviolet light) type Ozonator
The UV Ozonator is normally installed in-line after the pools existing filtration system. The UV light source built into the ozonator blasts the water passing through it with high levels of UV rays that destroys a large percentage of waterborne pathogens, including bacteria, viruses and algae.
The Ozone Generator type produces ozone gas which is injected into the pool water. The generator does this by splitting oxygen molecules into two parts that combine to make ozone.
The ozone gas is a very effective sanitizer and oxidizer that destroys most of the bacteria and viruses present in the pool water.
The Ozone gas also breaks down body oils and reduces algae in the pool water. The oxidization process causes finer contaminants to adhere to each other increasing their size making it easier for the pool filter system to remove them.
The result being a clear, clean and sanitized pool however like the other two, it is advised by some experts to add to the pool a low level of chlorine or bromine. Before applying check with your pool service/supplier.
PHMB (Polyhexamethylene Biguanide)
This is the only chemical currently available that eliminates the use of chlorine but it is not the total solution.
What is PHMB? It’s a positively charged (cationic) polymer that kills microorganisms in pool/spa water.
Usually sold as a liquid product containing 20% PHMB, it can help maintain a hygienic environment in your swimming pool.
Like other swimming pool sanitizers, PHMB is registered with the U. S. Environmental Protection Agency (EPA) for use in residential pools, however, public pools and spas require additional regulatory clearances. Several states have approved PHMB for use in public pools.
PHMB forms insoluble particles with some impurities in the water. Subsequently, these insoluble particles are captured in the pool’s filter system as the pool water is circulated, this results in a rise in back pressure.
As a consequence, pool filters should be backwashed more frequently. Depending on your geographic location, especially in warmer or tropical environments, more frequent chemical cleaning may be required.
PHMB does not oxidize and therefore remove all contaminants from the pool or spa water, therefore Hydrogen Peroxide needs to be used regularly to oxidize these contaminants.
It must be noted that some classes pool chemicals or treatment processes are incompatible with PHMB.
These include those we have mentioned above and include – Chlorine/bromine sanitizers, Copper-based algaecides, oxidizers, Electrolytic chlorine/bromine generators, Metal-based systems including ionizers and mineral systems, Corona Discharge (CD) ozone generators on pools.
For further advice you should contact your PHMB supplier, pool service store or company.
To apply PHMB to your pool pour the measured quantity in the water evenly around the perimeter with the circulation system running.
At the same time add hydrogen peroxide and compatible algaecide. Always read and follow the manufacturer’s instructions before applying.
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