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Thread: swg diagnostic disagrees with salt strips

  1. #1
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    swg diagnostic disagrees with salt strips

    still trying to get the trouble out of my trouble free pool...
    I think my issue is the same as Jeff74's, but I did not want to hijack his thread.
    My salt strips (new from tf kits this season) measure 3600, my swg (pentair ic40) measures 4500 on the diagnostic. I did 3 strips to be sure.
    I'm getting a high salt flashing green light on the unit.
    It has been doing this off and on since we got a power surge a few days ago. Not sure if the power surge has any bearing on this or not. When the ic40 was "happy" yesterday am, the diagnostic said the salt level was 4400. I think 4500 is the # that triggers the high salt light.
    I'm almost positive the unit is not making chlorine, because I had it on 60% overnight and the chlorine level did not budge.
    The pool was shocked per tfp a few days ago, all 3 criteria passed. I have maintained chlorine with 12% liquid so it has never dipped below 5.5, no ccs, so I doubt anything new is growing.
    I am planning on draining some water, bto see if that helps.
    Do you have any other suggestions?
    I'm ready to take out the swg, put in the dummy cell, and use bleach on the pool. or fill it in and plant flowers, whichever is easier.
    as always, thanks in advance for your help. I have been a very high-maintenance tfp'er this year.
    30000 gallon inground gunite pool
    Intelliflo ic-60 SWG, pentair tagelus sand filter, 1.5 hp whisperflo pump, tf 100 test kit,
    2 kids(tl), 1 mini-dachshund/lab mix(t),
    Central Illinois

  2. #2
    Administrator JasonLion's Avatar
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    Re: swg diagnostic disagrees with salt strips

    It is at least as likely that the SWG is correct about the salt level as the test strips being correct. Regardless, it is the SWG that needs to be kept happy, not the test strips. It is extremely likely that if you only replace a little water the salt level will come down and everything will start working normally.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    TFP Admin. Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  3. #3
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    Re: swg diagnostic disagrees with salt strips

    that's what I was hoping. my pool is otherwise balanced so I didn't want to dump a lot of water.
    30000 gallon inground gunite pool
    Intelliflo ic-60 SWG, pentair tagelus sand filter, 1.5 hp whisperflo pump, tf 100 test kit,
    2 kids(tl), 1 mini-dachshund/lab mix(t),
    Central Illinois

  4. #4
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    Re: swg diagnostic disagrees with salt strips

    i'm having this same problem but I drained almost 1/3 of my water and refilled and still says HI on SWG. Strips said 2800 and pool store (gasp) says 3300...not generating....brand new cell.....turned off the power to reset it and still have the same issue. any suggestions?
    18,000 gallon in ground SWG sand filter electric cover

  5. #5
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    Re: swg diagnostic disagrees with salt strips

    In case anyone is watching this thread and has the same issue with the ic40, it still will not produce any chlorine. Probably because it fluctuates between reading 4350 and 4500 on the diagnostic display. 4500 must trigger it to shut down. Called the pb, he suggested draining a foot, not just a few inches off like I had done already, to really drop the salt level and see how the ic40 does then.
    I'll post a follow up when I have one. It will be 90 and sunny here this week so I would really like to fix this!
    30000 gallon inground gunite pool
    Intelliflo ic-60 SWG, pentair tagelus sand filter, 1.5 hp whisperflo pump, tf 100 test kit,
    2 kids(tl), 1 mini-dachshund/lab mix(t),
    Central Illinois

  6. #6
    Senior Member MattM's Avatar
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    Re: swg diagnostic disagrees with salt strips

    fyi, I wouldn't trust the test strips at all. I tested the salt level in my pool today via four methods:
    a) SWG reading - said 3550 which seemed correct
    b) pricey salt only test strip that takes 10 minutes to reveal level -- it read 2,200
    c) cheap salt only test strip that has must be read within a 10 second window after waiting 20 seconds after dipping in pool -- I honestly am not sure what it was indicating - somewhere between 3500 - 4000 I think.
    d) the drop test available as add on to the tf100, took 2 mins to test, it read 3400

    As far as my SWG goes, if it reads under 3200 for several days in a row, I'll add one bag of salt.....my kids splash out alot of water so I'm putting in a bag roughly every 2 months. The SWG never reads above 3800 under normal circumstances.
    24K gallon inground gunite/pebble sheen pool, 34'x16' 4-7.5ft deep, 750sq ft solar, pentair ultratemp, intelliflow vs+, ic60, intellichem w/ acid pump, quad de 100, intellibright 5g, intellitouch i5-3s with Screenlogic2, 3" primary piping - 2.5" at equip pad, auto switched deep heating and main returns, automatic safety cover w/ electronic lock and embedded recessed undertrack, sealed stamped concrete deck, dolphin deluxe 5, started up December 2011.

  7. #7
    Senior Member Ohm_Boy's Avatar
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    Re: swg diagnostic disagrees with salt strips

    Basic SWG Theory lesson ("This porridge is too hot...")

    Pure water is not conductive at all, so current will not flow through it by applying electricity to it. Salt is added to water to make it conduct electricity. More salt, more electricity (current) flow.

    The SWG relies on the conductivity of the water to make chlorine. The more conductive the water, the higher the amps will be on the SWG. There is a limit as to how much current the SWG can safely pump through the cell, wiring, and connectors, so it will shut down at high current levels. Think of this like a circuit breaker - it's a safety protection for the SWG system.

    If the salt concentration is too low, electricity will not flow through the water in the cell, and no chlorine will be generated.
    If the salt concentration gets too high, the water will conduct electricity too readily, and will draw too much current from the SWG.

    Somewhere in between, the porridge is JUST RIGHT, and the SWG will be happy and produce chlorine and the worlds water will be safe for another day.

    So do not read the strips and argue with the SWG. If the SWG ain't happy, ain't NOBODY happy.
    [center:1kpalu48]Helpful Links: Pool School | CYA/Chlorine Chart | Pool Calculator[/center:1kpalu48]

  8. #8
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    Re: swg diagnostic disagrees with salt strips

    I have definitely learned my lesson! still adjusting levels, update soon...

    funny thing, I just got this sign as a gift yesterday, change the wording slightly for swg's:
    Attached Images Attached Images
    30000 gallon inground gunite pool
    Intelliflo ic-60 SWG, pentair tagelus sand filter, 1.5 hp whisperflo pump, tf 100 test kit,
    2 kids(tl), 1 mini-dachshund/lab mix(t),
    Central Illinois

  9. #9
    Senior Member Ohm_Boy's Avatar
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    Re: swg diagnostic disagrees with salt strips

    Yep, that's the quote I stol... er... modeled my response after.
    [center:1kpalu48]Helpful Links: Pool School | CYA/Chlorine Chart | Pool Calculator[/center:1kpalu48]

  10. #10
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    Re: swg diagnostic disagrees with salt strips

    Quote Originally Posted by Ohm_Boy
    Basic SWG Theory lesson ("This porridge is too hot...")

    Pure water is not conductive at all, so current will not flow through it by applying electricity to it. Salt is added to water to make it conduct electricity. More salt, more electricity (current) flow.

    The SWG relies on the conductivity of the water to make chlorine. The more conductive the water, the higher the amps will be on the SWG. There is a limit as to how much current the SWG can safely pump through the cell, wiring, and connectors, so it will shut down at high current levels. Think of this like a circuit breaker - it's a safety protection for the SWG system.

    If the salt concentration is too low, electricity will not flow through the water in the cell, and no chlorine will be generated.
    If the salt concentration gets too high, the water will conduct electricity too readily, and will draw too much current from the SWG.

    Somewhere in between, the porridge is JUST RIGHT, and the SWG will be happy and produce chlorine and the worlds water will be safe for another day.

    So do not read the strips and argue with the SWG. If the SWG ain't happy, ain't NOBODY happy.
    What's the JUST RIGHT amount then

    /no matter how hard I try, the porridge is either too hot or too cold
    14x42 Intex Ultra Metal Frame approx 4,000gal

  11. #11
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    Re: swg diagnostic disagrees with salt strips

    I agree with the1jake! I'm still goofing around with my swg trying to get it right.
    It seems to have survived its' high salt experience but needs to run 60% for 24 hours per day right now. PB suggested an acid clean, so I'm going to get a 5 gal bucket tomorrow and give that a try.
    salt level is 3900 right now according to the diagnostic, and at least its producing chlorine now!
    (pentair ic40)
    30000 gallon inground gunite pool
    Intelliflo ic-60 SWG, pentair tagelus sand filter, 1.5 hp whisperflo pump, tf 100 test kit,
    2 kids(tl), 1 mini-dachshund/lab mix(t),
    Central Illinois

  12. #12
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    Re: swg diagnostic disagrees with salt strips

    I agree that the SWG reading is most probably the most accurate with one exception and that is the Taylor Industries Salt Water Test kit, it is expensive but seems to be highly accurate within 200 ppm. Unfortunately it seems the chemicals go off after a year even if ordered directly from them and stored properly giving an inaccurate reading after a year. This results in another expensive reagent purchase. Also if you get the solution on your fingers it stains them black/grey for days.

    The test strips in my opinion are a joke, the last time I purchased one it was so far off that I went down to the pool store and purchased another from the same company but a slightly different use by date, this gave a completly different reading but too far to the opposite side. These strips are made by what some persons call a reliable company whom I will not mention.
    10,000 gal plaster pool,3/4 hp WhisperFlo pump, Sta-Rite Great White GW9500 pool cleaner, Hayward 300 lb Sand Filter
    Use Magenta Stuff for Iron and Silica control.
    Balance: pH 7.7 Cl 7 -8 Alk 70-80 CH 325 CyA 30 in winter - 50 in summer NaCl 1010 TDS 1200

  13. #13
    Administrator JasonLion's Avatar
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    Re: swg diagnostic disagrees with salt strips

    The Taylor salt test is +-400 in this situation, and it can be wrong too though not as often as the test strips.

    You should visually inspect the cell. If you don't see any white crusty stuff there isn't any reason to clean it.

    How long you need to run the cell is very dependent on your other levels. If you post a complete set of test results we might spot something that needs adjusting. It is also possible you have a low level algae problem, and overnight FC loss test can confirm or disprove that possibility.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    TFP Admin. Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  14. #14
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    Re: swg diagnostic disagrees with salt strips

    I do see white crusty stuff on the inflow end of just the center plate, so PB suggested acid wash.
    noob question here: I need to shut off power to the swg to clean it. Not sure how to do that except to flip the circuit breaker to the easy touch controller on my house electrical panel. Any reason why that would be a bad idea?

    tests tonight:
    fc=5.5. cc.5
    pH 7.7
    TA. 140 (trying to bring this down)
    CH 220
    CYA. added 3.5# on 5/23 to raise to 65ish
    salt 3900 on e.t. diagnostic
    temp 80
    water slightly hazy cl never dropped below 5 so I dont know what to make of that.
    so I'll do an over night loss test but I did one several times after I did the last shock and it was fine
    thanks for all your help. I'm pretty lost here and more than a little tired of not having my pool trouble free yet
    30000 gallon inground gunite pool
    Intelliflo ic-60 SWG, pentair tagelus sand filter, 1.5 hp whisperflo pump, tf 100 test kit,
    2 kids(tl), 1 mini-dachshund/lab mix(t),
    Central Illinois

  15. #15
    Administrator JasonLion's Avatar
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    Re: swg diagnostic disagrees with salt strips

    Turning off the circuit breaker for the whole ET sub-panel while working on the SWG cell is fine.

    The high SWG percentage and run time is at least partly because of your low CYA level. We recommend CYA be between 70 and 80. As the CYA level comes up you will be able to turn down the percentage or run time (or both). Cleaning off the calcium scale will also have an effect. If you fix both of those things will improve noticeably.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    TFP Admin. Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  16. #16
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    Re: swg diagnostic disagrees with salt strips

    that sounds so encouraging!
    I was trying to sneak up on the CYA level, thats why I aimed so low. so much easier to add than to remove CYA.
    30000 gallon inground gunite pool
    Intelliflo ic-60 SWG, pentair tagelus sand filter, 1.5 hp whisperflo pump, tf 100 test kit,
    2 kids(tl), 1 mini-dachshund/lab mix(t),
    Central Illinois

  17. #17
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    Re: swg diagnostic disagrees with salt strips

    ok, just washed the cell. it only bubbled a bit, so I let it sit for only 10 minutes or so, then reinstalled.
    water still slightly hazy, maybe a bit better than yesterday. I'm sure since I just cleaned the cell I need to let the pool turn over a few times to see if the haziness had anything to do with having a dirty cell.
    do my test results suggest any other reason for cloudiness?
    passed oclt
    fc 8.0/cc 0. I added some after I tested this morning and my newly cleaned ic40 must have kicked in some Cl too. I turned it way down just now so cl can drop a bit.
    pH 7.6
    CH. 210
    TA 150
    salt swg says 3600
    CYA. just added, hopefully 65ish

    TA is pretty high, I thought it would go down more quickly with acid additions every night, but it does not. I was wondering if TA was contributing to haziness. I was thinking about following the "how to lower your TA" directions, but if I get more agressive with the acid and lower the pH to 7.2, that will make the csi -.5. I know the pH will rise quickly, but I wasnt sure that was safe for the plaster.

    The other possible culprit for the haziness is there is some scaling, could the calcium be dissolving back off the plaster and cause haziness (probably a crazy theory, but I had to ask)
    30000 gallon inground gunite pool
    Intelliflo ic-60 SWG, pentair tagelus sand filter, 1.5 hp whisperflo pump, tf 100 test kit,
    2 kids(tl), 1 mini-dachshund/lab mix(t),
    Central Illinois

  18. #18
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    Re: swg diagnostic disagrees with salt strips

    I've had a thread open for a long time with the same problem. (salt test readings, not haziness)

    Compupool says 3400
    Strips say 2610
    Taylor Drops say 6400

    I've considered calling CompuPool, but have simply decided for now to trust the SWG. I figured that it was what needed the right salt content. Was glad to see others chime in and say I did the right thing.

    And that's with water temp of 85 and perfect pool chemistry otherwise.
    Built in 1957 44,000 gallon in-ground, Wet Edge Primera Stone in Sky Blue, Intelliflo VF Pump, 600 lb. Pentair Triton II T100 Sand Filter, CompuPool CPCS48 SWG, TF-100 test kit

  19. #19
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    Re: swg diagnostic disagrees with salt strips

    still hazy, no improvement.
    I'll do another oclt to see how that goes.
    I never had so much trouble last season!
    I spoke to Pentair and my PB and it may be time to look into replacing the cell.
    Possibly damaged it when I got the salt too high or when we had a power surge.
    30000 gallon inground gunite pool
    Intelliflo ic-60 SWG, pentair tagelus sand filter, 1.5 hp whisperflo pump, tf 100 test kit,
    2 kids(tl), 1 mini-dachshund/lab mix(t),
    Central Illinois

  20. #20
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    Re: swg diagnostic disagrees with salt strips

    My neighbor had an issue with a high salt reading, when we knew that the salt level wasn't that high. It ended up that the system had reset the software for a different cell than the T-15 he was using. A simple reset to the proper cell and problem solved.
    chiefwej
    Tucson, AZ
    19k gallon Pebble Tec pool/spa, 2 hp Super II pump (x2), Aqua Rite T-15 SWG, Pro Grid 60 DE filter, Hayward H400 & Solar heating

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