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Thread: SWG flow and chlorine production

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    SWG flow and chlorine production

    I have my SWG wired to the low speed outputs on my timer. It is a Compupool replacement for a Jandy Aquapure 1400. Here is my issue: when the pump is running on low, which is how I would like to do it most of the day, the cell itself is only 1/3 to 1/2 of the way full. The flow is fine for the SWG to operate, but I am concerned that a) the electrolysis plates might get damaged because there is no water on the upper portions of the plates, and b) my chlorine generation is being severely compromised or the cell is thinking it is generating much more than it is (since water is not flowing over parts of the plates). Was wondering if anyone has run into this - at this point, my only thought is to perhaps run the SWG only on the high speed side, but that would ramp up the cost quite a bit.

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    chiefwej's Avatar
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    Re: SWG flow and chlorine production

    Are you running the SWG set at 100% output? If not, that's one solution. Run the pump at higher speed but shorter time with SWG set for highest output.
    chiefwej
    Tucson, AZ
    16x36 rectangular (19k) Pebble Tec play pool/spa, Pentair Intelliflo VS 011018, Super II 2hp (spa), Aqua Rite T-15 SWG, Pro Grid 60 DE, Hayward H400 & Heliocol Solar heating, A&A infloor system, fill water w/high CH and TA, 50 ppm borates,TF-100 test kit

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    robdac's Avatar
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    Re: SWG flow and chlorine production

    Welcome to the forums!

    I don't understand how the pump speed could be related to whether or not the SWG is full of water. If the pump is on then the cell should be full at all time.

    If you run the pump on high does the SWG fill completely with water?

    If you then turn the pump back to low will it remain full?

    How long has this been going on?
    11K gal IG screened-in plaster pool w/ spa
    pentair 150 cartridge filter, Pentair Intelliflow VS pump,
    Aquarite AQR15 SWG, AquaCal Heatwave Heat Pump, TF-100 test kit

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    Re: SWG flow and chlorine production

    If I run the pump on high, the SWG is full of water. On low, I guess the volume is not sufficient? I've noticed this ever since I put in the two-speed pump. I had the SWG wired up to the high-speed timer output before but re-wired it when I replaced the cell so that I can run low-speed most of the day and minimize high-speed. I've also noticed that the pressure gauge on the filter (I have a DE 60-lb Jandy filter) reads next to 0 at low speed and where it should be only on high speed. Don't know if that is normal or indicates a bigger problem.

    The pump is able to prime fine, so there are no suction-side leaks. There is no pressure-side leakage visible. It is doing what it is supposed to as far as I can tell. It is a Hayward Super II 1.5HP 2-speed that I have since replaced the motor with a Regal Beloit STS1152R.

    - - - Updated - - -

    I have not taken note of what happens when it is running on high and I switch it to low. I believe the water level drops in the SWG, but I will verify later today.

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    Re: SWG flow and chlorine production

    What brand SWG do you have? I have a Hayward, and it is plumbed in a vertical line from my filter down into the ground. I have a VS pump and even on low speeds, the cell is always full of water. At a higher RPM, the only difference is the rate at which the water passes through, not volume at any given moment. If I run my VS pump at less than 1000 RPMs, then I have a low flow issue and the cell doesn't generate. Is this last statement what you are talking about?
    5900 G Fiberglass IG pool (circa 1990), SWG Hayward Aqua Rite GoldLine (2013), IntelliFlo Variable Speed Pump (2013), Hayward Pro Sand Filter (circa 1990), Well water (no iron or other metals fortunately), test with Taylor K2006C, Charleston, SC

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    Re: SWG flow and chlorine production

    I have a Compupool replacement for my original Jandy 1400 cell. The SKU is GRC/J/APURE1400-3. It is plumbed horizontally, and since part of it is translucent, you can tell that the water is only a part of the way up while it is flowing through. The pump motor is a 2-speed, 3500/1750, so the low speed is 1750 rpm. The flow indicator is lit and the SWG is ok with the flow, but that is across the sensor which is plumbed up in the bottom, so it is always covered with a layer of water. Since the electrolysis plates are positioned vertically in the cell, the result is that the upper half of each one is not in the water when it is operating. I don't know if that is causing any issues or will lead to the cell dying quickly. I will post some pics, I think that will help illustrate.

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    Re: SWG flow and chlorine production

    Mine is horizontal andbalways full. If your pipes are not full 100% of the time, you must have a leak somewhere.
    16 x 32 17500 gallons
    Vinyl in-ground
    Hayward 250# Sand Filter
    1 HP Pump
    Hayward SWG

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    Re: SWG flow and chlorine production

    Quote Originally Posted by dbspcl47 View Post
    If I run the pump on high, the SWG is full of water. On low, I guess the volume is not sufficient? I've noticed this ever since I put in the two-speed pump. I had the SWG wired up to the high-speed timer output before but re-wired it when I replaced the cell so that I can run low-speed most of the day and minimize high-speed. I've also noticed that the pressure gauge on the filter (I have a DE 60-lb Jandy filter) reads next to 0 at low speed and where it should be only on high speed. Don't know if that is normal or indicates a bigger problem.

    The pump is able to prime fine, so there are no suction-side leaks. There is no pressure-side leakage visible. It is doing what it is supposed to as far as I can tell. It is a Hayward Super II 1.5HP 2-speed that I have since replaced the motor with a Regal Beloit STS1152R.

    - - - Updated - - -

    I have not taken note of what happens when it is running on high and I switch it to low. I believe the water level drops in the SWG, but I will verify later today.
    It is normal for the filter PSI to read near zero when running a 2-speed pump on low-speed.

    I have a feeling that it is also normal for there to be gas in the cell while running on the pump on low-speeds. The Jandy flow sensor is not like most flow sensors and relies on water covering the probes. When enough gas builds up in the cell, the probes in the sensor get exposed to the gas and sends the "no flow" error message. When the pump is running on high-speed there is enough water flow to push the gas out of the plumbing so it does not build up inside the cell.

    Now the question comes down to does running the pump most of the time on low-speed cause any issues with the lifespan of the cell and does it cause the cell not to put out the full amount of chlorine that it is capable of producing? Just adding my two cents, I think both issues are valid concerns. It makes sense that it can not produce the full amount of chlorine since not all of the plates are not covered with water all the time. That exposure time of the water against the plates is when the chlorine is generated and if half the plates are not exposed to water I can not see how it possible to generate chlorine on those areas not exposed to water. As far as the lifespan goes that is harder to determine. In my own experience when I had a Jandy Aquapure SWG I ran a good portion of the time on high-speed for the first 2 years and my original cell lasted 2 years 10 months and was replaced under warranty. The replacement cell only lasted 1.5 years and that cell was run 90% of the time on low-speed.

    I have now switched to a Hayward AquaRite SWG and noticed a difference in the amount of calculated chlorine usage in the pool. With the Jandy cell, which was mounted horizontally, I calculated that it produced 4.2 ppm of chlorine a day during the summer months. Our pool is used for lessons 8 hours a day and is in full sun. This summer with the Hayward, mounted vertically, the pool only needed 3.2 ppm of chlorine a day. I have a feeling that gas does not build up in the cell when it is mounted vertically but that is only a guess. The design of the Hayward cell might also lead to less build up of gas, but that is just a guess.
    16k gal plaster with raised spa, Jandy DEV60 filter, 2 HP 2-speed SHPF Jandy Stealth pump
    Hayward Aqua Rite T-15 SWCG, Jandy LXi 400k BTU NG heater, 350 sq.ft. of Sun Star solar panels, TF-100 Test Kit, Dolphin s300i Cleaner
    Test Kits . Pool Math . Chlorine/CYA Chart . The SLAM Process

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