Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 11 of 11

Thread: Trouble with salt readings - strips vs. SWG

  1. Back To Top    #1

    Join Date
    Jun 2007
    Location
    Arlington, VA
    Posts
    29

    Trouble with salt readings - strips vs. SWG

    I just opened my pool and am having trouble with the salt readings.

    Test strips (a couple of years old) show the salt level at 3540, which is surprising since that's about where I thought I left it last year before closing.

    The reading on the Aquapure SWG shows 2400.

    The pool temperature is only about 64 degrees, but there is nothing in the Aquapure documentation that shows that would affect the salt calculation.

    Which number should I believe? Could the higher reading be the result of old and faulty test strips?
    ____________
    34,000 gallon pool with charcoal Marquis aggregate finish
    Jandy stealth pump, cartridge filter and Aquapure SWG
    Solar heating with Goldline controller
    Polaris 380 Blackmax

  2. Back To Top    #2

    Join Date
    Jul 2007
    Location
    Brisbane, Australia
    Posts
    874

    Re: Trouble with salt readings - strips vs. SWG

    temperature does affect salt calculations as most of the SWG measure current vs voltage or in best case - conductivity

    i would trust the salt strips more but i would get fresh ones

  3. Back To Top    #3
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: Trouble with salt readings - strips vs. SWG

    I have found that the salt test strips tend to go bad quickly after their expiration date. I would not trust strips that were past their expiration date.
    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

  4. Back To Top    #4

    Join Date
    Jun 2007
    Location
    Arlington, VA
    Posts
    29

    Re: Trouble with salt readings - strips vs. SWG

    Thanks. It was the test strips. They didn't expire until next month but were bad already.

    New strips showed a reading of 2500, basically agreeing with SWG.

    Now to get the salt - we use a maintenance guy to open and he owes us the 200-ish lbs of salt we need.

    I am always shocked at the volume of salt needed when we have to adjust our 34,000 gallon pool. Just for grins I plugged it into the pool calculator and it would have required almost 1000 lbs on initial start up! I wasn't around when our pool builder did it but especially since he used Mineral Springs Beginnings that must have cost a pretty penny...
    ____________
    34,000 gallon pool with charcoal Marquis aggregate finish
    Jandy stealth pump, cartridge filter and Aquapure SWG
    Solar heating with Goldline controller
    Polaris 380 Blackmax

  5. Back To Top    #5

    Join Date
    Jun 2007
    Location
    Arlington, VA
    Posts
    29

    Re: Trouble with salt readings - strips vs. SWG

    Resurrecting an old thread as I'm having the same problem with my just opened pool. The SWG reads low salt, 2300. Probably low due to the cold temperature, but still. The "new" test strips I bought last spring, with an expiration date of 2/2011 are reading 4000. Cannot possibly be right.

    I will order new test strips but the expiration date on these things seems to have zilch to do with when they actually go bad.
    ____________
    34,000 gallon pool with charcoal Marquis aggregate finish
    Jandy stealth pump, cartridge filter and Aquapure SWG
    Solar heating with Goldline controller
    Polaris 380 Blackmax

  6. Back To Top    #6
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    21,932

    Re: Trouble with salt readings - strips vs. SWG

    This makes me wonder what the storage requirements are to get them to last till the expiration date??
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

  7. Back To Top    #7

    Join Date
    Jun 2007
    Location
    Arlington, VA
    Posts
    29

    Re: Trouble with salt readings - strips vs. SWG

    Good question. They were stored over the winter in a heated space.
    ____________
    34,000 gallon pool with charcoal Marquis aggregate finish
    Jandy stealth pump, cartridge filter and Aquapure SWG
    Solar heating with Goldline controller
    Polaris 380 Blackmax

  8. Back To Top    #8

    In the Industry
    Pool Clown's Avatar
    Join Date
    Sep 2008
    Location
    Silicon Valley, CA
    Posts
    1,578

    Re: Trouble with salt readings - strips vs. SWG

    Doesn't anyones local pool store check salinity with an accurate, non test strip device?
    Factory Warranty Station for:
    Jandy/Zodiac, Pentair, Sta-Rite, Raypak, Polaris,
    and Paramount pool cleaning systems.

  9. Back To Top    #9

    Re: Trouble with salt readings - strips vs. SWG

    Mine do. I believe they have a unit that measures conductivity....
    17,200 in ground Vinyl pool......
    Salt Water
    Sand Filter

  10. Back To Top    #10

    Join Date
    Jun 2007
    Location
    Arlington, VA
    Posts
    29

    Re: Trouble with salt readings - strips vs. SWG

    What local pool store? :P (The closest one to me is at probably 10 miles away, in DC area traffic ...)
    ____________
    34,000 gallon pool with charcoal Marquis aggregate finish
    Jandy stealth pump, cartridge filter and Aquapure SWG
    Solar heating with Goldline controller
    Polaris 380 Blackmax

  11. Back To Top    #11

    Join Date
    Dec 2009
    Location
    Central Massachusetts
    Posts
    2,690

    Re: Trouble with salt readings - strips vs. SWG

    Quote Originally Posted by Pool Clown
    Doesn't anyones local pool store check salinity with an accurate, non test strip device?
    Mine does. Almost always comes within 200-300 ppm of my IC-40 reading. The salt strips are usually off by close to 800-1000 ppm (higher reading, not lower)
    14,000 gallon IG, Vinyl. Hayward 3/4 hp superpump, Penatair IC40 SWCG, Pentair automation, Hayward sand filter, Aqua Comfort heat pump, Hayward 400k Lo-Nox LP heater.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •