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Thread: Check my assumptions on SWG understanding

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    foobert's Avatar
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    Check my assumptions on SWG understanding

    Do I understand correctly that the output percent adjustment changes the amount of time that the cell is actually powered, ala, pulse-width modulation at the respective percentage of on-time? Thus, if electric costs are ignored, would there be any difference to cell life between running for 4 hours per day at 100% vs 8 hours at 50%?

    I see that the Autopilot systems have a 3-step current adjustment. If the daily chlorine output were equalized between the 3 current settings (i.e. low current-->more hours, high-current-->fewer hours on), does one mode lead to longer cell life than another?

    And finally, how does a properly cleaned and cared for cell go bad at the end of it's life? Does the generated chlorine output slowly decline to the point that 24 hours of run time no longer produces the necessary CL2? Or is it typically a binary failure mode -- worked yesterday and now it doesn't?

    For reference, I'm looking at the Auquarite w/ -15 cell, vs a Nano/Digital w/ -42(-48?) cell. I've already read many of PoolSeans pitches on the merits of the autopilot system, so I'm not looking to turn this into another one of those threads.
    ~john
    24.5K G, pebble, SuperFlo VS 1.5, 48sq DE filter, Hayward H250FDN, Autopilot RC-52, Poolvergnuegen & 3 daily swimmers in season.

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    JoyfulNoise's Avatar
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    Re: Check my assumptions on SWG understanding

    Quote Originally Posted by foobert View Post
    Do I understand correctly that the output percent adjustment changes the amount of time that the cell is actually powered, ala, pulse-width modulation at the respective percentage of on-time? Thus, if electric costs are ignored, would there be any difference to cell life between running for 4 hours per day at 100% vs 8 hours at 50%?
    Yes, it's a "duty cycle" method of powering the cell so 8hrs/50% is equivalent to 4hrs/100%.

    Quote Originally Posted by foobert View Post
    I see that the Autopilot systems have a 3-step current adjustment. If the daily chlorine output were equalized between the 3 current settings (i.e. low current-->more hours, high-current-->fewer hours on), does one mode lead to longer cell life than another?
    I have a Pentair IntelliChlor which is a constant voltage power supply. So not sure how the other systems work.

    Quote Originally Posted by foobert View Post
    And finally, how does a properly cleaned and cared for cell go bad at the end of it's life? Does the generated chlorine output slowly decline to the point that 24 hours of run time no longer produces the necessary CL2? Or is it typically a binary failure mode -- worked yesterday and now it doesn't?
    The plates are titanium (in good quality cells) coated with a transition metal oxide (ruthenium, rhodium, platinum) catalyst layer. The catalyst layer wears down after a while and exposes the titanium. The titanium will anodize in water and effectively become non-conductive. The reduced surface area shows up as a "low salt" alarm and FC production diminishes. Eventually the power supply will clamp at high voltage or current and the whole system just starts to produce less chlorine.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    Mod Squad Jimrahbe's Avatar
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    Re: Check my assumptions on SWG understanding

    Foobert,

    Just curious.. if you already have an "automated chlorine system", which is in your signature, why do you want to install a SWG? Keep in mind that in the winter, the SWG will shut off, and you will have to add chlorine/bleach anyway.

    Jim R.
    Finished in 2015 - 17K Gal, IG, 20' x 25' Almost Rectangular Pool, Pebble finish, three rockport water falls. Pentair Equipment: EasyTouch 4, IC40 SWG, 3 HP VS Pump, CCP520 Cartridge Filter.
    TF100 with SpeedStir and SampleSizer, ColorQ Pro 7, Dolphin Premier Robot Cleaner, added Screen Logic 2, added small 3 person Calder Spa.

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    foobert's Avatar
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    Re: Check my assumptions on SWG understanding

    Mostly, I'm tired of lugging jugs of bleach around. Lessor issue was that it always required more fidgeting than I was happy with to keep it maintained (plumbing issues, predominately).

    Edit: Also, I can re-purpose the system to do acid injection w/ the SWG, so, it won't go to waste. It will be much happier not pushing quarts of fluid per day through it
    ~john
    24.5K G, pebble, SuperFlo VS 1.5, 48sq DE filter, Hayward H250FDN, Autopilot RC-52, Poolvergnuegen & 3 daily swimmers in season.

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    Re: Check my assumptions on SWG understanding

    As far as "PWM" is considered, on many units the "pulse" is for the duration that the internal timer switches it on, rather than a pulse width that would correspond to a frequency greater than 1 hz. But running time accumulates the same either way.
    16X32 AB, Pentair SD filter, 3/4hp Pentair Optiflo, CircuPool RJ30+ swg, TF 100

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    foobert's Avatar
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    Re: Check my assumptions on SWG understanding

    Quote Originally Posted by JoyfulNoise View Post
    The plates are titanium (in good quality cells) coated with a transition metal oxide (ruthenium, rhodium, platinum) catalyst layer. The catalyst layer wears down after a while and exposes the titanium. The titanium will anodize in water and effectively become non-conductive. The reduced surface area shows up as a "low salt" alarm and FC production diminishes. Eventually the power supply will clamp at high voltage or current and the whole system just starts to produce less chlorine.
    OK. So, over time, I should expect to see a gradual increase in run-time as the cell ages. I'm on time-of-use electric metering with an 8 hour window of "cheep" power to get the bulk of pump run-time completed. W/ a 1.4lb/day cell, 8 hours yields 2.2ppm increase in FC at 100% duty cycle -- just about right, but, no headroom for production decline.
    ~john
    24.5K G, pebble, SuperFlo VS 1.5, 48sq DE filter, Hayward H250FDN, Autopilot RC-52, Poolvergnuegen & 3 daily swimmers in season.

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    Re: Check my assumptions on SWG understanding

    Quote Originally Posted by Jimrahbe View Post
    Foobert,

    Just curious.. if you already have an "automated chlorine system", which is in your signature, why do you want to install a SWG? Keep in mind that in the winter, the SWG will shut off, and you will have to add chlorine/bleach anyway.

    Jim R.
    I'm a noob to the SWG, just had inground pool installed and had SWG added. I saw your comment regarding the SWG shut off in winter. I expect that in my area the water won't get below 60 in Dec-Feb which is within the range for my SWG. PB didn't mention anything about winter months, is there something that I need to be concerned with?
    Free Form 13K IG (Quartz) w/Screen Enclosure - 2 Sheer Descents, 1 Bubbler - Hayward 60 SF DE Sta-Rite - Hayward SP3400VSP EcoStar - Hayward Aqua Rite AQR9 (T-Cell-9) SWG - Zodiac MX6 - July 2016 - Taylor K-2006 - Taylor K-1766 Salt Test

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    Mod Squad Jimrahbe's Avatar
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    Re: Check my assumptions on SWG understanding

    Bob,

    I'm not sure about your particular SWG, but on mine (Pentair IC40) a light actually comes on saying the unit is shut off due to cold water. I think in theory it shuts off at 52 degrees, but in reality it seems it is closer to 55 to 57 degrees.

    I believe that most SWGs operate in a similar fashion. Not really an issue, as you don't need much chlorine when the water is that cold anyway, but something to keep in mind.

    Jim R.
    Finished in 2015 - 17K Gal, IG, 20' x 25' Almost Rectangular Pool, Pebble finish, three rockport water falls. Pentair Equipment: EasyTouch 4, IC40 SWG, 3 HP VS Pump, CCP520 Cartridge Filter.
    TF100 with SpeedStir and SampleSizer, ColorQ Pro 7, Dolphin Premier Robot Cleaner, added Screen Logic 2, added small 3 person Calder Spa.

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    JoyfulNoise's Avatar
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    Re: Check my assumptions on SWG understanding

    Quote Originally Posted by foobert View Post
    OK. So, over time, I should expect to see a gradual increase in run-time as the cell ages. I'm on time-of-use electric metering with an 8 hour window of "cheep" power to get the bulk of pump run-time completed. W/ a 1.4lb/day cell, 8 hours yields 2.2ppm increase in FC at 100% duty cycle -- just about right, but, no headroom for production decline.
    Can you afford a larger, 2lbs cell (IC60 or AutoPilot RC52)? I think there's even a 3lb cell available.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    needsajet's Avatar
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    Re: Check my assumptions on SWG understanding

    Larger cell would be nice and life-cycle cost improves with a larger cell, so if it were mine, I'd go with a different brand to get a larger cell and sort out the control aspects.

    That said, the VS pump is beneficial because you might be able to dial down the speed and increase run time to give you some FC production headroom when needed. I guess that might extend past the overnight electricity rates, but at least provides an option.
    12k IG salt; glass beads in plaster; K-2006C, K-1766, CCL, and Aussie 4in1 (HTH); Pentair Eco800 1.2HP VS; Zodiac SWC 1.3 lb/day (25 g/hr); 25" filter recycled glass; OKU solar panels; 1/2 HP solar pump; Rebel (Warrior) pool cleaner; FlowViz; prior pool AG 10k | Read Before Posting to get the best possible advice | ... and this helped me a lot!: TFPC for Beginners

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    foobert's Avatar
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    Re: Check my assumptions on SWG understanding

    I'm going to go ahead and step up to the 2lb/day cell. That rules out the more economical Aquarite system, but, I suspect the Autopilot will be a less fiddly system anyway. Placing the order tomorrow.
    ~john
    24.5K G, pebble, SuperFlo VS 1.5, 48sq DE filter, Hayward H250FDN, Autopilot RC-52, Poolvergnuegen & 3 daily swimmers in season.

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