Aerating with oxygen

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Aerating with oxygen

Postby pooltalk » Fri 05 Jun, 2009 23:36

Hello
I am new to this forum and new to pools in general. We just bought a 32'x12'x48" Intex, Oval Above Ground Pool that used chlorine. We bought a salt-generator and had it set up for two days thinking this would be safe but then realized that chlorine is chlorine and that apparently it causes bladder cancer and various other cancers and even read that some places are banning salt-generated pools. So since I already have a compromised immune system (hence why we got the pool in the first place- for me to get exercise and get better), we decided to turn it off and figure something else out. My husband happened to have a oxygen pump and he put it in the pool off the side this evening and it is now blowing oxygen and generating bubbles in the water and thereby aerating the pool. We think that oxygen will raise or keep the pH, alkaline, so the algae won't grow. We thought maybe we could also add baking soda into the water in a couple of days after all the chlorine, that the salt-generator produced, goes away. We read somewhere to use 1lb of baking soda for every 6ooo gallons, for 4 days. Our pool is approx. 7400 gallons. Does anyone have any idea if we will be succussful in our mission or have any suggestions or ideas on what we could do to solve this inexpensively?
:thumbup:


chem geek
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Aerating with oxygen

Postby chem geek » Sat 06 Jun, 2009 09:28

Blowing oxygen into the pool isn't going to prevent algae growth.

It's not chlorine itself that causes health issues, but what is known as disinfection by-products (DPBs) which is chlorine combined with various organics and ammonia compounds. Virtually all reports of respiratory (including asthma) and ocular problems are associated with indoor pools and these generally are pools with no Cyanuric Acid (CYA) in them so the active chlorine level is orders-of-magnitude higher than in a pool with CYA as with most outdoor pools exposed to sunlight. That combined with the UV of sunlight helping to break down some DPBs and better air circulation removing volatile ones more quickly has an outdoor pool exposed to the sun and with CYA be much, much, much safer.

Basically, you are being needlessly scared away from chlorine on the basis of significant over-chlorination of most indoor pools in the U.S. In a pool where the Free Chlorine (FC) is around 10% of the Cyanuric Acid (CYA) level, the active chlorine concentration is roughly the same as a pool with 0.1 ppm FC and no CYA. It is very, very low.

Nevertheless, I appreciate your concern to want to minimize your exposure to chlorine so there are ways to do that at extra cost while still getting the benefit of sanitation from chlorine. Basically, you need something to kill algae since the main reason you need as much chlorine as found in most pools is to prevent algae growth. Killing bacteria and inactivating viruses takes far, far lower chlorine levels unless one has a commercial/public pool and wants to be extra safe against person-to-person transmission of disease (i.e. to have faster kill times). If you were to use a weekly PolyQuat 60 algaecide or to use a phosphate remover (including maintenance doses), then you could maintain a very low chlorine level by having 1 ppm FC with 80 ppm CYA which is a very, very low amount of active chlorine. You could also use 50 ppm Borates (in addition to either algaecide or phosphate remover), though check with your doctor regarding boric acid which is what the main form of borates is in a pool -- ask if soaking in 50 ppm boric acid going to be OK for you (note that boric acid is often used as a disinfecting wash at far, far higher concentrations).

Also, read Water Balance for SWGs and note that the Borates (as well as a lower TA) are also helpful in preventing the pH from rising as quickly, since that is a common issue in SWG pools.

If you absolutely, positively didn't want any chlorine at all, then the level of risk jumps up in terms of bacterial growth and since you have a compromised immune system I would think you would be more concerned with that than with DBPs.

Richard
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Aerating with oxygen

Postby Me... » Sat 06 Jun, 2009 09:32

I read that post and thought, "Mmm I hope chem geek gets in here and responds." Well said and I too was thinking that if I had a compromised immune system I would be paying special attention to keeping my free and total chlorine levels in order.
pooltalk

Aerating with oxygen

Postby pooltalk » Wed 10 Jun, 2009 00:22

I really appreciate your replies and I have referenced your link chemgeek. It sure doesn't look like there is an alternative to chlorine even with the salt-water generators. I have no idea how safe 1ppm of pure chlorine will be for my immune system but I've emailed someone from BeyondHealth.com who might know if the salt-generated chlorine is safer than the regular chlorine (which needs various other chemicals to stabilize it). My husband still hasn't plugged the salt-water generator back in and has just had the water aerating and it actually doesn't look like there is a problem with it but it's been raining and we've been busy so we haven't checked the pH and such but the water still looks great. Thanks a million for your replies.
chem geek
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Aerating with oxygen

Postby chem geek » Wed 10 Jun, 2009 09:25

The chlorine in a saltwater chlorine generator (SWG) pools is IDENTICAL to the chlorine added from any other chlorine source (Trichlor, Dichlor, Cal-Hypo, chlorinating liquid, bleach, lithium hypochlorite). The only difference in an SWG pool is that it has a higher salt level. Your statement that regular chlorine "needs various other chemicals to stabilize it" is not true. Cyanuric Acid (CYA) is needed to protect ANY chlorine from breakdown from sunlight, even in an SWG pool, and it is also useful to moderate chlorine's strength.

The automated dosing and super-chlorination in the salt cell may let you run at a somewhat lower FC/CYA ratio in an SWG pool, but I had already mentioned other approaches such as using an algaecide or phosphate remover that can be used to keep the chlorine level as low as possible.

Clear water is not sanitary water. It just means you have no visible algae, but bacteria, viruses and other pathogens can be in the water while it is still clear. Bacteria can double in population every 15-60 minutes. That means that under ideal conditions, one bacteria can become more than 4 billion in 8 hours.

If the person you E-mail at BeyondHealth.com knows anything about chemistry, then refer them to this link which is the definitive 1974 paper that determined the chlorine/CYA equilibrium constants. My cursory look at BeyondHealth.com isn't very positive. This is probably why you got scared about chlorine without an understanding of the difference between indoor and outdoor pools, volatile disinfection by-products vs. chlorine in water, the chlorine/CYA relationship, etc. I would be vary wary of ANY website that sells you something.

Also, keep in mind that it's not 1 ppm FC you are really being exposed to (unless you were to drink the swimming pool water), but rather the equivalent of 0.01 ppm FC if there were no CYA in the water. That is, the CYA in the water at the levels I'm talking about (around 80 ppm or so) reduces the active chlorine (hypochlorous acid) concentration by roughly that factor of 80 and that slows down chlorine reaction rates by that same amount. The only issue would be whether the chlorine combined with CYA were to be absorbed through the skin in any significant quantities and that seems less likely (the primary species is a negatively charged larger molecule whereas hypochlorous acid looks somewhat like water and is neutral in charge). Unfortunately, though toxicology studies have been made on cyanurates (see here ) showing them to be rather benign except at high concentrations, there isn't anything I can find on skin absorption rates for the chlorinated cyanurates (chlorine combined with CYA) except for this paper and its two relevant references from swimming. This paper indicates minimal skin absorption of cyanuric acid so it is likely that the chlorinated cyanurates have minimal absorption as well since they are of a similar structure and as I noted the most common are negatively charged so even less likely to enter cells (cells have a negatively charged surface and only generally uptake specific negatively charged chemical species through ion channels and is the main reason why hypochlorite ion is so much less effective than hypochlorous acid as a disinfectant).

I again repeat that I believe you should be more concerned about having your pool be properly sanitized against pathogens given your compromised immune system than you should be concerned about chlorine, especially in the conditions we've been talking about (i.e. outdoor pool exposed to sunlight with good air circulation and using CYA to moderate chlorine's strength). I strongly suggest you talk to a competent physician and not use alternative health websites as your guide towards keeping yourself safe with your specific health condition. It's not that some alternative methods aren't good, but most of these sites don't know much science and are primarily just promoting their own products (for profit). In this latter sense, they aren't much better than most drug companies except that they are less regulated.

I'm not trying to scare you into using chlorine. For sure, using oxygen or even an ozonator alone is NOT going to be sanitary since you need SOMETHING in the bulk pool water killing pathogens faster than they can reproduce. Even using metal ions or an algaecide would be better than nothing at all, but would not be nearly as good as even a small amount (low FC/CYA ratio) of chlorine. There are only two other strong bulk sanitizers: bromine and Baqua/biguanide/PHMB. Bromine breaks down in sunlight so isn't great for an outdoor pool and some people are sensitive to bromine or don't like it's smell. Baqua/biguanide/PHMB is expensive and after some years of use can allow white water mold to grow. A properly managed chlorine pool really is the most effective, inexpensive approach (though in your case for "minimal" chlorine, it will cost more since you'll need weekly algaecide and/or phosphate remover).

Richard

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