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Thread: Chemical sensors and feeders

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    Join Date
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    Chemical sensors and feeders

    Does anyone here use chemical sensors and feeders?
    We just had a ORP/PH sensor feeder installed and I am lost on setting this thing up.
    It came with relatively no instructions and the guy who installed it didn't know anything aside from how to install the pumps,etc.
    The biggest question I have is how to calibrate the ORP/Chlorine level. I know basically that the ORP is just a sanatizer level....but I do I equate that to what my tests are reading for chlorine level.
    I'm not even sure how to explain it but hope someone on here is familiar with them and can shed a little light on the subject for me.
    Thanks for your help.
    Deena
    http://www.lindbrookstargazer.ca
    100,000 liter IG vinyl liner
    Rolachem Chlorine & Muratic acid Auto feeders/Pool Perfect Auto feeder
    Pentair 30" filter (Tagelus) Sand filter/Centruion switchless pump 1.5/.25 HP

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    JasonLion's Avatar
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    It is generally recommended to aim for an ORP reading of 650. How much FC that corresponds to will depend on your CYA level. If the CYA level is too high it won't work correctly. ORP readings are very sensitive to PH, does your system regulate PH as well? There are other things that can interfere with ORP readings, metals in the water, disolved hydrogen gas from a SWG, etc.

    You should post the brand/model of your controller and a full set of test numbers and we can give you some more specific advice.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  3. Back To Top    #3

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    Rola-Chem ORP/pH digital controller

    It's a Rola-Chem Model 554 ORP/pH digital controller. We are feeding 12% chlorine and muratic acid.
    pH 7.5
    FC 5.49
    TC 6.08
    CH 400
    TDS 1500
    Phos 1000

    ORP is set at 650 and pH at 7.2

    I know my CYA numbers are high so I had been running chlorine levels around 8-9 to keep the CC down.
    I'm hoping that now that I am using unstablaized chlorine that my CYA number will eventually come down without a big pool drain/water exchange.

    I have the chlorine feeder feeding for 10 seconds out of every 5 minutes right now and the pH set at 7.2
    ORP was at 650 this morning and pH was at 7.3
    The feed light for the pH stays on so I'm not sure if there is an issue there, it doesn't feed but the light stays on.

    At this point this may just be more of a means to feed extra chlorine during the day when I have extra swimmers but if anyone has any ideas/insight/advise on getting the most of this system for now and for when my CYA numbers come down I'd sure appreciate it.
    Deena
    http://www.lindbrookstargazer.ca
    100,000 liter IG vinyl liner
    Rolachem Chlorine & Muratic acid Auto feeders/Pool Perfect Auto feeder
    Pentair 30" filter (Tagelus) Sand filter/Centruion switchless pump 1.5/.25 HP

  4. Back To Top    #4
    JasonLion's Avatar
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    Do you have numbers for CYA and TA?

    You want your CYA level below 50 for the ORP sensor to give consistant results. CYA won't come down by it's self except possibly over the winter. To lower CYA you need to replace water.

    I would set the goal PH to 7.4. Lower PH will partially compensate for the higher CYA level, allowing the sensor to work a little better, but low PH can also cause skin/eye irritation. I think that 7.2 is a bit low. If you get the CYA level is below 40 then a PH of 7.5 is probably ideal. The PH feed has probably been on constantly for a while trying to bring the PH down from 7.5 to 7.2.

    I wouldn't worry about CC less than or equal to 0.5. Direct sunlight will take care of it after a while as long as your FC level remains reasonable. I can't say if your FC level is appropriate or not without a CYA number.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  5. Back To Top    #5

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    Chemical sensors and feeders

    Sorry....forgot to add the
    CYA 100
    TA 122

    I can say already this has been a huge help in that we can add chlorine through out the day during heavy bather load. We've been able to keep our numbers up despite the load, which is something we could not do before without closing the pool.
    I know I need to get my chlorine up to at least 8 to get my CC to zero.
    Just not sure that my local health unit is going to be ok with that.
    Thanks for your help.
    Deena
    http://www.lindbrookstargazer.ca
    100,000 liter IG vinyl liner
    Rolachem Chlorine & Muratic acid Auto feeders/Pool Perfect Auto feeder
    Pentair 30" filter (Tagelus) Sand filter/Centruion switchless pump 1.5/.25 HP

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    Tonights numbers

    pH 7.3
    FC 4.39
    TC 4.39
    CH 400
    Alk 109
    Phos 1000
    TDS 1500
    CYA 100
    (ORP 615 pH sensor 7.3)
    I seem to have achieved the zero CC but it is irratic. I think it's happened maybe 3 times this week, sometimes at high numbers and sometimes at around the 4 mark.
    I don't really understand how or why that is working????
    Deena
    http://www.lindbrookstargazer.ca
    100,000 liter IG vinyl liner
    Rolachem Chlorine & Muratic acid Auto feeders/Pool Perfect Auto feeder
    Pentair 30" filter (Tagelus) Sand filter/Centruion switchless pump 1.5/.25 HP

  7. Back To Top    #7
    JasonLion's Avatar
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    CC comes from FC interacting with organic contaminants in the pool and partially breaking them down. Additional FC and sunlight will then break them down further into things you don't need to worry about. That process takes a little while and in the mean time if there are additional organic contaminants the FC will go to fighting the new stuff before it deals with the CC.

    Since your CYA level is so high you need to have your FC level up between 8 and 15 for there to always be enough FC to break down the CC. The CYA will tie up most of the chlorine at any given moment. When there isn't enough FC things will go back and forth, depending on the bather load and amount of sunlight as CC will sometimes be created more quickly than it is getting broken down and sometimes slower.

    You need to either lower your CYA level, which requires replacing water, or raise your FC level. Probably you will need to do both, raise your FC level for now and work on replacing water to get your CYA level down.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  8. Back To Top    #8

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    Thanks

    Thanks for all the info.
    I think you are right in that I am going to have to do a partial drain to get my CYA numbers down.
    I've certainly learned my lesson about trusting people who "claim" to be pool professionals.
    I had my doubts about my pool guy last year and I should have followed my gut but I was mostly handling the chemicals and things were alright.
    This year I had him come in 2 days while I was in a course to vacumm and test the pool and when I came back he had added way too much Cyanuric acid and about 10 kg of stabilized chlorine.
    We actually had to neutralize the pool to get the chlorine levels down but there is not repairing the CYA levels without a partial drain.
    Now, no one adds anything to my pool except me.....then if I'm wrong and mess up I only have myself to blame.

    Thanks again for all your help.
    Deena
    http://www.lindbrookstargazer.ca
    100,000 liter IG vinyl liner
    Rolachem Chlorine & Muratic acid Auto feeders/Pool Perfect Auto feeder
    Pentair 30" filter (Tagelus) Sand filter/Centruion switchless pump 1.5/.25 HP

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