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  1. #1
    Anonymous [GDPR] European in the UK Guest

    Default Domestic pool turnover rates

    Quote Originally Posted by mas985 View Post
    First the whole concept of turnover for residential pools is flawed (see pump run time study in my sig). There is no minimum turnover required for a residential pool so minimum flow rates are really only important for things such as heaters and SWGs and SPAs so you really don't need to bother trying to figure it out unless you have one of these features.

    No need to. A pool can get by with as little as 2 hours of run time (see study).
    I couldn't agree more Mark,
    The chlorine kills what it can in under a minute, what isn't killed by chlorine has to be filtered out. How quickly should this be filtered out? should it be a hour or 8 hours? If the filtration isn't good enough then the whole lot is just recirculated so you spend on electricity achieving very little.

    The only thing I couldn't see in your pump run time study is a turbidity measure of how clear the water was. It seemed to me it was just an observation?
    I filter my water 24/7 using my energy efficient system, this achieves a better result than a short pump run time for several reasons.
    1. The dirt and debris actually go into the skimmers because the system is running so a lot less makes it to the bottom which is what happens when a system is off.
    2. This slower rate filtration improves the filtration process by a factor of 4 so catching much finer particles ie it actually removes the fine stuff and improves the turbidity. Conventionally this was 5NTU now 0.5-1 NTU.
    3. The power consumed by a conventional system in 2 hours of running is sufficient to run my pool for 24 hours.

    Why did turnover rates ever become popular as they tend to be the focus rather than the really clean clear water achieved by proper filtration which begins when you half the hourly flow rate figure written by the manufacturers on their filter information.

  2. #2
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    Default Re: Domestic pool turnover rates

    Quote Originally Posted by Teapot View Post
    The chlorine kills what it can in under a minute, what isn't killed by chlorine has to be filtered out. How quickly should this be filtered out? should it be a hour or 8 hours? If the filtration isn't good enough then the whole lot is just recirculated so you spend on electricity achieving very little.
    I am not sure what you meant by this but you really shouldn't try to filter out live bacteria or live algae or it will clog the filter. The only thing that should be filtered out of a pool are dead organics and debris.

    As for turbidity, I run for only 2-4 hours per day and have never had any signs of turbidity. I don't think it is a real issue for most pools.
    Last edited by mas985; 07-23-2015 at 08:20 PM.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

  3. #3
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    Default Re: Domestic pool turnover rates

    Quote Originally Posted by mas985 View Post
    As for turbidity, I run for only 2-4 hours per day and have never had any signs of turbidity. I don't think it is a real issue for most pools.
    What considerations would increase that run time? We have debris from out arbor vitae trees falling into the pool all the time, and we can't be out there manually skimming all the time. Would just 2-4 hours per day on high be enough and then a good chunk more on low be OK?
    26,000 gal IG vinyl liner pool (20'x40'), Waterway SMF-110 wet end w/ Century SQS-1072R motor, Pac-Fab Triton TR60 sand filter, K-2006A. Manually added chems: 12.5% NaClO liquid, granular CYA, baking soda, 31% muriatic acid.

  4. #4
    Anonymous [GDPR] European in the UK Guest

    Default Re: Domestic pool turnover rates

    Quote Originally Posted by mas985 View Post
    I am not sure what you meant by this but you really shouldn't try to filter out live bacteria or live algae or it will clog the filter. The only thing that should be filtered out of a pool are dead organics and debris.

    As for turbidity, I run for only 2-4 hours per day and have never had any signs of turbidity. I don't think it is a real issue for most pools.
    As I said chlorine will kill what in can in under a minute, that would be lots of different bacteria, virus's etc including algae spores so that's the job done except for chlorine resistant types, like Giardia and Cryptosporidium and oocysts which need filtering out (this depends on the filtration being good enough and may also need flocculent. Generally the pumps are too big and the filters too small to achieve great filtration, eyesight is too bad to judge.

    If you filter for 2-4 hours only and that is sufficient it may of course depend on where you live and your pool is situated with tree debris etc but with the water stationary for 20-22 hours of the day anything entering will become water logged and sink. This may not effect turbidity whilst no swimmers are in the pool but swimmers and quickly the water becomes cloudy. The same with vacuuming the pool the little dust cloud that gets stirred up in front of the vac head which leaves the pool slightly less clear than before you started.

    If the system is running 24/7 then the detritus gets into the skimmers not to the bottom of the pool. It seems to take barely any energy to circulate the chemicals to keep it all mixed but you do need a flow across the pool of a minimum 22 gallons per minute to make the skimmers system work (for a pool of my size 24 x 12) Jets are carefully arranged to mix the water and over a period of time the water gets clearer and clearer. OK, I am no longer using sand so the filtration is far better in terms of how fine it filters which is more important as electricity should be put to good use trapping fine particles and not recirculating them which is what happends when the pump is too large for the filter.

    I have run many pools the old way and then experimented and unequivocally the water is cleaner, clearer and takes less maintenance when run 24/7 and turbidity dropped from 5 NTU's (very clear) to 0.5-10 NTU's (incredibly optically clear) AS far as I can ascertain there is nothing to be gained from short pump runs where the power is equal to 24 hour running. I am not saying you can't run short times and be happy with the result but done the other way 24/7 on very low energy (around 50watts/hour in my case but that's 39 watts over night) Not everyone could do this but even a 1/8th-1/4 hp pump would be more than sufficient for most pool filtration and just keep the old pump for vacuuming and backwash. I use a pool blaster max for the occasional leaf that misses the skimmer of the bit of dirt from after the rain.

  5. #5
    CarlD's Avatar
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    Default Re: Domestic pool turnover rates

    This is bad advice and not something we can endorse. The whole philosophy of OF is making things simple, inexpensive and effective. Running 24/7 unless you are fighting a bloom is wasting money. And you sound like you are arguing against vacuuming. Not going to fly here.

    Self-described experts are not accepted at face-value here.
    Carl

  6. #6
    Anonymous [GDPR] European in the UK Guest

    Default Re: Domestic pool turnover rates

    Carl, please don't take this the wrong way, it's not bad advice it's different advice. What is OF?
    Making things simple, inexpensive and effective are my bywords to.
    24/7 isn't wasting money when the cost is less than your pump running for two-three hours.
    Not arguing at all.
    Vacuuming is necessary but less so, I sold my pool robot as it was not needed the pool doesn't get that dirty any longer.

    Ben is a Pioneer, this forum is great but does that mean there isn't another alternative? I have run many pools the old way and they are more work, 24/7 has a drawback to, you have to empty the skimmer baskets more frequently as that's where the debris ends up, not on the bottom.
    This is new low energy running, only possible because new parts come along.
    This idea is better for management and better for the environment. CO2 levels need to be reduced, according to a University calculator my pool produces 128kg of CO2 by comparison a conventional pool (3/4 hp) would produce 2 tons of CO2.
    CO2 is causing the oceans to become acidic, on the present graph the fish will begin to die by 2015, if there is another way to run things shouldn't we look at it?
    http://news.nationalgeographic.com/n...ic-oceans.html
    http://www.awi.de/en/news/background...g_more_acidic/

    "Self described experts are not accepted at face value here", no problem, I am not selling a product, no junk science gadget just a concept that I have spent a few years exploring and installing on my customers pools. People can choose their own ways I just wanted to add something to the debate.

  7. #7
    CarlD's Avatar
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    Default Re: Domestic pool turnover rates

    The math doesn't add up. I run my pool at low 12hrs a day solely to keep my solar panel decking cool and the water warm. Running it 24/7 will NOT save me money, it will cost money. You are not understanding Mark's point.

    Different ideas have to be proven before we allow them given as advice here. And many have been, including, for example, SWCGs, high borate levels, and TA levels below "standard range" to name a few. But they all have been proven, not merely asserted.

    If you want to continue this, take it to the China Shop until you can prove it.
    Carl

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