Hi - I didn't find anything specific on a quick search of TFP... are THMs of concern to the typical residential pool owner? My understanding is that testing for them is very expensive (?) -- any insights from the experts?
Trihalomethanes (THMs)
- Thread starter FattyLumpkin
- Start date
- May 23, 2015
- 24,543
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Nope, not really a concern in a clean swimming pool.
The only source of THMs in a pool would either be huge amounts of organic matter left in the pool (like soil and decomposing leaves, etc) or large amounts of sweat and urine. The most likely THM would chloroform but, at typical FC/CYA ratios and with plenty of UV light from the sun, formation would be very low and residual concentrations almost undetectable.
THMs in pools are really only a problem for public pools and especially those public/commercial pools that are indoors. In those instances, a secondary oxidation source is a good idea (either UV or a contact tank with ozone or ozone+peroxide).
THMs are more of a concern in a chlorinated or brominated hot tub where bather loads are exponentially higher. Even in that case, simply opening the cover for an hour or two each week with the jets running would be enough to expel most THMs.
The only source of THMs in a pool would either be huge amounts of organic matter left in the pool (like soil and decomposing leaves, etc) or large amounts of sweat and urine. The most likely THM would chloroform but, at typical FC/CYA ratios and with plenty of UV light from the sun, formation would be very low and residual concentrations almost undetectable.
THMs in pools are really only a problem for public pools and especially those public/commercial pools that are indoors. In those instances, a secondary oxidation source is a good idea (either UV or a contact tank with ozone or ozone+peroxide).
THMs are more of a concern in a chlorinated or brominated hot tub where bather loads are exponentially higher. Even in that case, simply opening the cover for an hour or two each week with the jets running would be enough to expel most THMs.
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