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Non Chlorine Alternatives

If you don’t like using chlorine in your pool there many alternatives you can use instead. The alternatives can be banded in to two groups – low chlorine and no chlorine. As the names suggest you have the choice of doing away with chlorine altogether or cutting its use to a very low dosage. The important fact to know is that chlorine is cheap and easy to use and non-chlorine alternatives are not cheap and not so easy to use. But don’t let the expense or extra maintenance required put you off changing, once you have experienced swimming in low or no chlorine water you will never go back!

Before going in to non-chlorine alternatives lets just remind ourselves what chlorine does and why it is so popular. It does the three top jobs required in your pool.

* (1) It kills bacteria very quickly at quite low concentrations.* (2) At higher concentrations it kills algae.* (3) It breaks down oils, lotions, skin flakes etc. (also known as 'bather waste')

Chlorine is not without its problems though, the two main ones are that when it reacts with certain organic material it forms chloramines and they are smelly. It is chloramines that give that 'chlorine' smell to a pool and can sting your eyes. Secondly, it only works properly when the pH of the pool is correctly adjusted. Chloramines and bather waste can be broken down by adding more chlorine, this is called 'shocking' your pool water.

Chlorine does everything and does it all by itself and just as important, though often overlooked, it is easy and very cheap to test how much Chlorine is in the pool. If you use alternative chemicals to do jobs (2) and (3) then you can cut the dosage of chlorine quite dramatically if all it has to do is kill bacteria. It is important to realise that, apart from Bromine, there is no one single chemical you can use to replace chlorine so you always have to use at least two or three.

Here is a list of the things the domestic pool owner can use to replace chlorine, each one is discussed in detail below.

* Bromine* Persulphates (also known as Active Oxygen)* Ozone* Copper and Silver* Polymeric Biguanides (also known as Baquacil and Revacil)

Bromine [No Chlorine]

The first obvious alternative to Chlorine is Bromine. It is in the same family of chemicals as Chlorine and is chemically very similar. It kills in the same way but it does form its own equivalent of chloramines called bromamines. Bromamines, however, are not too bad. Not only do they not smell anything like as much as chloramines they are actually a disinfectant in their own right so although we’d prefer not to have them they still kill bacteria so we don’t bother getting rid of them. Bromine is also more tolerant of high pH and high temperatures. This is why it is often used in spas.

Chlorine comes is many forms but Bromine always comes in inch high mini tablets. You feed it to your pool via a floating dispenser or a brominator, which a glorified tube with pool water running through one end and a lid at the other. It does all three top jobs but you may need to 'shock' your pool to rid it of bather waste. You can use chlorine shock or non-chlorine shock. It is as easy to test for as chlorine but is 50% more expensive.

Persulphates (also known as Active Oxygen) [No Chlorine]

Persulphates work in much the same way as Chlorine to jobs (1) and (3). They kill bacteria and break down bather waste but they are not very effective against algae. You always need some other product to kill algae if you use Persulphates. They are often referred to as 'Active Oxygen' systems. This trips off the tongue better than potasium monopersulphate and sounds more space age.

The most commonly used Persulphate is just known as 'Non-Chlorine Shock' it is generally used just to shock the pool in order to break down bather waste. It breaks it down to atoms so it is effectively a chemical filter because it smashes visible particles to invisible atoms. It can be used in a chlorine pool instead of Chlorine shock and you can swim in the water an hour after application, not the case with Chlorine shock. Non-Chlorine shock is popular with spa owners.

The Germans love these types of sanitisers and the German company Bayrol are the leaders in these systems. They market a product called Soft and Easy and Bayrol Duo tabs. Soft and Easy comes in sachet form and Duo Tabs are two tablets that you put in the water. Both are a combination of a quaternary algicide and a blend of persulphates. Bayrol sell a test kit for their products.

Persulphates are expensive compared to Chlorine. You have to use twice as much by weight and it costs 50% more. A typical Chlorine shock dose costs £2.00 a Persulphate dose would be about £6.00.

Ozone [Low Chlorine]

Ozone is a very unstable and toxic form of oxygen. Normally oxygen atoms join together in pairs to form a very stable O2 molecule. Ozone is three oxygen atoms together and one of them will jump off and kill any organic material in a flash. It is by far the fastest killer. It is however highly toxic and is not permitted to be present in pool water.

It is generated in a special unit that attaches to the pipework of the pool which is powered by electricity. They only act on the water in the pipe at the time and they have to be designed to do all the killing within the unit and not let any ozone out. Because of this you still need to keep what is know as a 'residual' level of Chlorine in the pool water to keep on top of anything entering the pool. The level required is 0.5 to 1.0ppm but this is much lower than the regular amount and barely detectable by bathers. You will need a good algicide to keep algae out and will have to shock the pool with Non Chlorine Shock. They cost about £750.00 for a big pool and need an expert to fit them. Many spas have mini versions added to them but you still need chlorine in the water.

Copper and Silver (also known as Natural Minerals) [Low Chlorine]

Copper is very good killer of algae albeit a bit slow compared to chlorine. Cowboys knew what they were doing when they put a silver dollar in their drinking water to keep it safe to drink because silver is a very good, but slow, killer of bacteria. There are two ways to get copper in to pool water either as copper ions, that is copper atoms, but with a charge, or combined with another compound known as a chelating agent. The chelating agent holds on to the copper until it finds an algea spore to jump on to. Copper reacts with the chlorophyll in algae and stops it from absorbing light and so kills it.

Silver can not be added to your pool using a chelating agent. It must be added as silver ions. Copper and silver are naturally occurring elements in the earth’s crust so the marketing chaps can just about get away with claiming that by using them you are using 'natural minerals' to sanitise your pool.

The most common way to add copper and silver to your pool is with an Ioniser. These can cost as little as £400.00 and are quite easy to install with out expert help. They attach to your pipework and run on electricity. They have a copper and silver electrode that erodes away over time as the pool water passes over it. You usually need to replace the electrodes every year and, being made of silver, they are not cheap. There is a test that you can do for copper but you can not test for silver so it is assumed that the silver gets used up at the same rate as the copper but this is not always correct.

Like Ozonators they only act on the water in the pipe at the time. Because of this you still need to keep what is know as a 'residual' level of Chlorine in the pool water to keep on top of anything entering the pool. The level required is 0.5 to 1.0ppm but this is much lower than the regular amount and barely detectable by bathers. You will have to shock the pool with Non Chlorine Shock from time to time.

Other products that use copper and sliver but not via an ioniser are Nature2 and FROG. They are easy to fit to your pipework and trap the algae in little balls containing the copper and silver. They cost about £300.00 and need re-fills every 6 months which are about £100.00.

A new kid on the block is the Floatron. This is an ioniser using only a copper electrode but it floats on your pool surface and uses a solar cell as its energy source. At about £250.00 with electrodes that are claimed last up to 24 months and cost £30.00 to replace it is better value than the FROG and Nature2 system.

Polymeric Biguanides. (also known as Baquacil or Revacil) [No Chlorine]

The best know polymeric biguanide is polyhexamethylene biguanide (PHMB) but for the purposes of this article we’ll call it Baquacil. Baquacil keeps the water sanitised but it needs help from BaquaCheck and BaquaShock. BaquaCheck is an algicide and BaquaShock is 36% Hydrogen Peroxide solution used as a shock treatment to break down bather waste.

Baquacil is totally incompatible with chlorine and before you use it you must get all of the chlorine out of the pool. Likewise if you change your mind and go back to Chlorine you must get all the Baquacil out. You can not use persulphates with Baquacil either.

Like all non-chlorine alternatives is expensive and has its own rather tricky testing system. It is not a popular system in this country and is not without its critics, particularly in the USA, but those that do use it seem to love it.


Hopefully this article has given an insight in to the various ways of cutting down or eliminating Chlorine from your pool. Non-Chlorine alternatives cost more and require more maintenance but we think it is worth it for the improved water quality.

Our recommendations? For Low Chlorine an Ioniser, for No Chlorine the Bayrol Soft and Easy system.