UV (ultraviolet) chamber will keep my pool algae free?

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Re: Alternative sanitizers and "chemical free" pools--The Tr

No way. Nothing you do only via the circulation system will prevent algae growth in the bulk pool water because any algae that stays stuck to pool surfaces will never get circulated. UV only affects the water passing under the UV light and there is no residual effect in the bulk pool water. The same is mostly true with ozone though it does last longer, but cannot be in high enough concentration in pool water because it could outgas and is an EPA regulated air contaminant (a component of smog). UV and ozone have only two real purposes -- 1) as a supplemental oxidizer to handle higher bather loads and 2) as a supplemental disinfectant against chlorine-resistant pathogens most notably the oocysts of the protozoa Cryptosporidium parvum.
 
Re: Alternative sanitizers and "chemical free" pools--The Tr

chem geek said:
No way. Nothing you do only via the circulation system will prevent algae growth in the bulk pool water because any algae that stays stuck to pool surfaces will never get circulated. UV only affects the water passing under the UV light and there is no residual effect in the bulk pool water.
Click to expand...

Ok. What if the pool surface is high gloss like Zeron?
Between that, a 30x20 pool, and a UV bombardment would the pool be kept pretty clear?

Thanks
 
Re: Alternative sanitizers and "chemical free" pools--The Tr

It takes time to turnover the water and in that time algae can grow. Algae double in population every 3 to 8 hours (best case) and one turnover of water only has 63% of the water pass through the UV system. So you'd have to have ideal circulation and very short turnovers.

If you truly want to not have halogens (chlorine or bromine) in the water, then at least use an algaecide such as Polyquat or use copper but keep its level controlled and the pH low to prevent staining or use a phosphate remover regularly. However, though this will control algae, it won't control fecal bacteria which is constantly being reintroduced whenever you have bathers in the water so a copper/silver combo would be better in that case. You can see relative kill times in this post.

Why are you wanting an algae-free pool without regard to whether the pool controls bacterial growth? At a minimum, one wants to prevent uncontrolled bacterial growth even if one doesn't care about the rate of person-to-person transmission of disease.
 
Re: Alternative sanitizers and "chemical free" pools--The Tr

Zeron is an epoxy pool surfacer that supposedly is so glossy that it's slippery (steps get textured)

I just don't like the idea of any -cidal chemicals, even copper.

I wonder if I could do some combination of: diminished sunlight with a pool enclosure, zeron high gloss surface, UV in-line system, and maybe even some "natural pool" swamp zone ...though I have no idea which plants starve algae growth.
 
If you don't like the idea of any bactericide or algicide, then you will be doing the equivalent of taking a bath using the same water over and over. Your bather waste will accumulate except for the small portion that gets broken up by UV. You might consider ozone instead or perhaps an advanced oxidation system such as boron-doped diamond electrodes to at least more thoroughly handle the bather waste. Bacteria will be shed from your skin and fecal matter and will grow in the pool. It will probably turn dull and cloudy as a result and you will increase your risk of getting diarrhea or worse. You most certainly won't be preventing any person-to-person transmission of disease. To minimize, but not eliminate, such uncontrolled bacterial growth, use an (expensive) phosphate remover which lowers the quantity of an essential nutrient.

If you want to swim in a "natural water" pool, aka swamp, then there are sphagnum moss systems available, but they won't keep the pool sanitary.

I don't understand why you won't use any form of -cide since algaecides such as Polyquat 60 are chemicals that only interact with microorganism cells of algae and bacteria and do not have the same affect on animal cells such as skin cells. You say you do not like the idea of having any -cide in the water, but do you like the idea of getting diarrhea? Do you like the idea of getting swimmer's ear? Do you like the idea of dying from Naegleria fowleri or other pathogens even though the risk is low (but much higher than if you used a proper disinfectant)?
 
Drinking water varies a lot, from 0.5 to 5 ppm (ppm is the same as mg/l). It is possible to have a pool that stays under 5 ppm nearly all of the time (unless you are shocking the pool), though you need to be careful to keep your CYA level fairly low, which may not be ideal for other reasons.
 
Any bad experiences in public pools was likely due to the presence of CC (combined chlorine) due to the higher bather load (like kids peeing in pool :)). These pools would actually have benefited from MORE Free Chlorine (FC) (to attack the organics and CC) rather than less, which would have made the problem worse.

If a pool has a chlorine smell, it is due to CC (need more FC). And eye irritation can again be due to CC or pH issues.
 

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Public pools have much, much higher bather load than a residential pool and many of them are not properly maintained. Indoor pools in particular are a problem because they tend to not use any Cyanuric Acid (CYA) so the active chlorine level is high.

Our recommendation for the Free Chlorine (FC) level relative to the CYA level has the equivalent active chlorine of less than 0.1 ppm FC with no CYA. That's less than 1/10th the amount you find in typical drinking water with 1 ppm FC with no CYA. When you take a bath with chlorinated water (not chloraminated which some water districts have switched to), the chlorine is reacting with your skin about 10 times faster than it would in a pool managed the way we recommend. The FC level is not relevant since you are not drinking the water -- the reaction rates are proportional to the FC/CYA ratio, not to the FC level alone (unless there is no CYA). Drinking/showering/bathing water that is chlorinated does not have CYA in the water to moderate chlorine's strength.

My wife personally experiences this difference between swimming in an indoor commercial pool over the winter where her swimsuits wear out, her hair is frizzier, and her skin flakier compared to using our own outdoor residential pool during the summer where such problems do not occur.
 
Good call! My pool water smells great, looks sparkly as can be and feels like heaven. All that's required is chlorine as the sanitizer and maintaining proper water balance.

Get your TA and pH dialed in, add some bleach and put some stablizer in a sock next to the return. You'll get there in no time.

Later you can advance to adding salt if you want a S)alt W)ater chlorine G)enerator (SWG) and/or borates for reduced chlorine demand, more stable pH and algaestatic properties.
 
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