Chemical Free Pool Systems?

Chlorinating, maintaining the right chlorine levels,
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Chemical Free Pool Systems?

Postby andrewhomes » Mon 17 Sep, 2007 01:00

I am sick of having chemicals in my pool. I am ready to go chemical free. I am sick of smelling like chlorine, in both my hair and skin. I have also got to know from aquabot that having a chemical pool has major health risks, like cancer and asthma. I want my family and I to be safe, so I have decided to switch to a chemical free pool.

I need to know about chemical free pool systems. What pool system is the best one? I have heard a lot from different chemical free pool companies. From ozone, to salt water pools, to other treatment types.

I need to know which chemical free pool system and company you prefer. I just have no idea which one to get, and which chemical free pool system is the safest, most effective pool system.

I also need the web address of the company, so I can check them out for myself. So if you have had any experiences with chemical free pool systems, and/or companies, please share.



Postby sonic » Wed 17 Oct, 2007 08:34

I have an 18 month old vinyl inground indoor pool. I was fitted with chemical free system (basically copper and oxgen added continupusly via electrolysis) and uv light to kill bacteria - ran with no chemicals for 2 weeks - pool went cloudy - now maintain about 1ppm free chlorine (only need to top up weekly - result crystal clear water, no chlorine smell, minimum effort - my view - a little Cl always required
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Postby chem geek » Wed 17 Oct, 2007 12:42

Salt water pools are NOT chemical free. They just use the salt (chloride) in the water to produce chlorine in a saltwater chlorine generator (SWG) cell. So any claim that this is chlorine-free is pure bunk. It is true that the disinfecting chlorine level in an SWG pool can usually be lower (an FC level of around 4.5% of the CYA level) due to the super-chlorination in the SWG cell though use of an algaecide can make that even lower (I talk more about that later).

Ozone and UV systems will only kill pathogens that float through those systems so it takes many, many hours before most of the pool water has been disinfected. It only takes 15 minutes to an hour for bacteria to double in population so such systems without a residual sanitizer will not be effective at disinfection (and are not allowed by the EPA to be used without a residual fast-acting sanitizer).

Residual slow-acting sanitizers such as silver ions or enzymes are at least present in the main body of pool water, but they are too slow acting to kill quickly enough. They may be OK to keep bacteria under control, but they do not kill quickly enough to get to very low levels and do nothing to kill the bacteria that come from the fecal route and are on their way to the oral route in yourself or from another person in just a few minutes (or less). The main purpose of a fast-acting residual sanitizer such as chlorine, bromine or biguanide (PHMB) is to kill pathogens faster than they can travel from fecal-to-oral.

As for the major health risks of cancer and asthma, this is again unsound exaggeration when it comes to outdoor pools that use Cyanuric Acid (CYA) in the water. ALL of the reports of asthma in children and competitive swimmers have been with INDOOR pools. This is because chlorine combines with ammonia and organics to form combined chlorines that are the hazardous chemicals and some of these are very volatile such as nitrogen trichloride (ammonia combined with three chlorine) and trihalomethane (methane combined with three chlorine). Such combined chlorines are readily broken down rather quickly in sunlight (similar to chlorine which also breaks down under sunlight if not protected by CYA) and is the main reason you rarely find combined chlorine in properly maintained outdoor pools while indoor pools have a harder time with them. The other difference is the much lower air circulation in indoor pools, especially these days where energy savings has minimized the amount of airflow (i.e. fresh air volume). Another difference that virtually no one has thought of is that indoor pools typically do not use Cyanuric Acid (CYA) because there is no sunlight to break down chlorine, but CYA acts as a chlorine buffer holding chlorine in reserve in relatively inactive form (as chlorinated cyanurates) so essentially indoor pools are overdosed with chlorine. 3 ppm FC with 30 ppm CYA in an outdoor pool is technically equivalent to having 0.1 ppm FC with no CYA in terms of the disinfecting chlorine (hypochlorous acid) concentration so that means that a typical indoor pool with 1 ppm FC and no CYA has 10 times the amount of disinfecting chlorine so is essentially being overdosed with chlorine. This results in a production of dichloramine and nitrogen trichloride (and possibly trihalomethane) that is nearly 10 times faster than in outdoor pools. Hair and skin degrade 10 times faster, chlorine outgasses 10 times faster, etc.

My wife has personal experience with this difference between indoor and outdoor pools. During the winter, she swims 5 months in an indoor pool with 2 ppm FC and no CYA and after just one season her swimsuits degrade (they are fade-resistant so don't fade much, but the rubber elasticity deteriorates) and her hair and skin are rough and the smell of chlorine byproducts is strong. During the 7 month summer season she swims in our outdoor pool with 3-5 ppm FC with 30 ppm CYA and there is no detectable degradation of the swimsuits (only very slight after 4 such 7-month seasons of use) and she rarely notices chlorine smell yet she is very sensitive.

Most pathogens found in pools are very easy-to-kill so only need a small amount of chlorine to do that. The main reason for the higher chlorine levels of an FC level that is at least 7.5% of the CYA level is to prevent algae. So the use of an algaecide such as PolyQuat 60 can let one use a lower FC level, perhaps 3% of the CYA level. The use of copper ions also act as an algaecide, but have side effects of green hair with blonds and can precipitate as stain if the copper level rises too much or the pH gets high. For killing bacteria, silver ions are a catalyst for oxidation so can help chlorine kill even faster so the combination of an algaecide plus silver ions could allow for rather low chlorine levels of perhaps 2% of the CYA level, but that would be about as low as one would want to go in order to ensure fast enough kill times for the fecal-to-oral route as the 99% kill time for easy-to-kill bacteria is around 4 minutes at this level of chlorine (without silver, so with silver perhaps it gets back under 1 minute).

Can you post a set of pool water chemistry numbers, especially the Free Chlorine (FC) and Cyanuric Acid (CYA) levels? Perhaps your pool is just overdosed with chlorine so you notice it more and that can be readily adjusted. Plus you can use a lower chlorine level by the methods I described above. Believe me, if my wife is happy with our pool I am sure that anyone except those with very rare allergies to chlorine can be satisfied. We looked at all sorts of alternatives when we got our pool, but finally settled on proper maintenance of a chlorine pool.

As for automated maintenance in a chlorine pool, the SWG system is one way to go, but you can also automatically dose with chlorine using The Liquidator which you can buy here.

[EDIT] One more point about supposedly "chemical-free" systems. Copper and silver are chemicals and in sufficient quantities they too are toxic. This is why the EPA limits the amount of copper to around 1 ppm and the amount of silver to around 50-100 ppb (0.05 - 0.1 ppm). There is no question that the relative toxicity of metal ion and enzyme systems at their normal dosages is lower than that of an improperly managed chlorine pool including indoor pools with no CYA where the disinfection by-products are high, but it is not at all clear that a properly managed chlorine pool is more toxic than these alternatives and in any event you need some chlorine with these alternatives anyway. Also, any non-chlorine chemicals powerful enough to rapidly oxidize organics in the water are also going to oxidize your skin and hair. The only difference is that you won't smell it.

Some people like the silkier feel and less eye pressure (from osmosis) underwater in an SWG pool, but that has only to do with the salt level and nothing to do with the SWG itself. [END-EDIT]

Allergy mom

Re: Chemical Free Pool Systems?

Postby Allergy mom » Tue 11 Jul, 2017 22:49

Hi Richard,

I've been reading all your scientific posts, and with twin 18 month olds with the very rare allergies you mention, what option of cleaning pool water would you recommend? We decided to get them a 103"x69"x22" above ground wading pool just for them to use. Only issue is we can't drain and fill every day, we need to find a way to clean the water without chlorine and heavy chemicals. Any suggestions?!?
Thank you!!!

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