Recent content by Retep

  1. R

    Floc and sand

    "Slow- rate " is faster than 0.1-0.4 meters/hour. You probably meant to say 1 - 4 meters/hour , and even this speed is very very slow. Drinking Water Plants run their Filters at about 7 meters/hour. "High-rate" is up to 20 GPM, which means not 12 meters/hour but 48.80 meters/hour. I also...
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    CO2 as a pH reducer - Problems with TA

    Thanks Jason - I knew there was a non-linear effect. Still - I think that by keeping a constant pH of 7.30 and a TA of 70 the consumption of CO2 should not be more as if I would keep the pH at 7.5 and the TA at 70. Naturally one would need a bit more quantities of CO2 at the beginning to...
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    CO2 as a pH reducer - Problems with TA

    Yeps - very serious. You just made me go back into my basement to look for those hand written notes from a public pool about 20 years ago. . . lol Bather load as well as Sodium Hypochlorite consumption was daily documented by the technical staff from this particular indoor swimming pool. Back...
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    CO2 as a pH reducer - Problems with TA

    I do remember coming across a study ( which I can't find anymore) which showed into more details the consumption rate in regards to the time being spent in the pool. Possible it was a bit longer than those 3 min. I stated. I find the chlorine demand you stated ( 4 grams / person) very low...
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    CO2 as a pH reducer - Problems with TA

    The majority of chlorine consumption per person happens right after the swimmer goes into the pool. If they stay 45 min it is only slightly higher than if they stay just 3 min. in the pool. (unless it is a competitive swimmer who sweats a lot and does heavy physical exercise in the pool ). As...
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    CO2 as a pH reducer - Problems with TA

    James - There are actually 2 Pools in this building. I described the bigger one ( 450.000 gal) , but the "Kiddie" Pool ( 65.000 gal) has more or less the same readings than the big pool. Turnover time on the big pool = once every 3 hours ( 8 times in 24 hours ) small...
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    CO2 as a pH reducer - Problems with TA

    IMHO a pH of 7.8 is way too high. 7.3 is good - if it's up to me I'd bring it down even lower ( 7- 7.2) but the municipality which owns the pool is afraid to to so, due to misinformation ( partly again by the pool builder). By running the pH at 7.8 the Hypochlourous Acid is probably only 1/2...
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    CO2 as a pH reducer - Problems with TA

    Thanks Jason and Chem Geek for your input. I also think the easiest and least expensive method would have been to simply use a liquid based pH reducer (e.g. muriatic acid 35 %). As we all know, there are always some political reasons and justifications involved when a municipality decides...
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    CO2 as a pH reducer - Problems with TA

    I came across a public indoor Pool ,which is using CO2 in order to bring down the pH. Sodium Hypochlorite is used as a disinfectant. Now : It seems the TA creeps up by using CO2 and more and more CO2 is used the higher the TA gets. . . Doesn't really make sense to me that CO2 brings up TA - I...
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    Interesting Study (Dissertation) on DBP's in indoor pools

    Re: Interesting Study (Dissertation) on DBP's in indoor pool Typically. Take a look at the members of the so called "advisory committee"and "Board of Directors" of NSPF. I do suspect it is not in their commercial interest to "lower down " suggested FAC levels in public pools. Basically the...
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    Interesting Study (Dissertation) on DBP's in indoor pools

    Re: Interesting Study (Dissertation) on DBP's in indoor pool There is probably nothing to panic about when you swim in an outdoor Pool - I do agree with you. Problematic is in the indoor pools and especially for the people who spend lots of time in the enclosed Pool environment. Basically...
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    Interesting Study (Dissertation) on DBP's in indoor pools

    Re: Interesting Study (Dissertation) on DBP's in indoor pool The risk of exposure to THM's in pool water is about 93 times ( ninety three) higher than exposure by tab water ingestion ! ( B.Levesque and Agazotti study) In other words - you could drink tab water up to 80 ppb of THM and the...
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    Interesting Study (Dissertation) on DBP's in indoor pools

    Re: Interesting Study (Dissertation) on DBP's in indoor pool Don't know what he got wrong there :?: If using sodium or calcium hypochlorites it raises the pH , therefore it must be lowered by (for example) Hydrochloric Acid ,and if using chlorine gas (to put it in simple words), we need to...
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    Interesting Study (Dissertation) on DBP's in indoor pools

    To my knowledge this is the first extensive study which examined indoor pools in the USA . It seems that finally attention is being paid on DBP's in order to protect public health. For good reason the German regulation (DIN 19643) limits the amount of THM's at max. 20 microgram/l. More and more...
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    Ideal ORP readings

    Richard, You posted ( at 4:06 pm )- I edited at the same time, so I guess you did not read what I added to my posting: Here it is what I added -> (from the World Health Organisation) -> 5.12.4 Oxidation–reduction potential Continuous control of the oxidation–reduction potential (ORP) is...