Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 6 of 6

Thread: Rapid drop in FC after adding chemicals

  1. Back To Top    #1

    Join Date
    Aug 2018
    Location
    New Smyrna Beach, FL
    Posts
    10

    Rapid drop in FC after adding chemicals

    This morning, the FC was at 7.5. I added the following:

    -40# Salt
    -2# Calcium increaser
    -3 qts CYA (liquid)

    5:00 comes around and FC was at 5.5

    Is there anything I added that combines with the chlorine to bring it down so fast?

    Thanks.



    8,000 gal, plaster, PlusHP 3/4hp pump, Jandy CS100 sqft cartridge filter, Jandy AquaPure ei SWG

  2. Back To Top    #2

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    31,199

    Re: Rapid drop in FC after adding chemicals

    The FC loss is not very fast at all......it's very close to normal.....about 2 ppm daily attributed to UV loss and organics being oxidized in your pool water.

    Why did you think it was too fast?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  3. Back To Top    #3

    Join Date
    Aug 2018
    Location
    New Smyrna Beach, FL
    Posts
    10

    Re: Rapid drop in FC after adding chemicals

    Quote Originally Posted by duraleigh View Post
    The FC loss is not very fast at all......it's very close to normal.....about 2 ppm daily attributed to UV loss and organics being oxidized in your pool water.

    Why did you think it was too fast?
    Mainly because the chlorine loss thus far from a SLAM recovery has barely been 0.5 loss/day. Then all of a sudden it dropped 2 ppm today with the addition of chemicals.

    The water temp is 68* and low UV as the pool is in a screened canopy and the sunlight gets filtered through dense trees (preserve on all sides of the yard).

    8,000 gal, plaster, PlusHP 3/4hp pump, Jandy CS100 sqft cartridge filter, Jandy AquaPure ei SWG

  4. Back To Top    #4

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    31,199

    Re: Rapid drop in FC after adding chemicals

    Given that new information, I can see your concern but I still do not believe there is a problem. I would test the water daily for maybe 3-5 days and see if your FC consumption doesn't level out.

    To answer your question, there is nothing in those 3 chemicals that contributes to chlorine loss.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  5. Back To Top    #5

    Join Date
    Aug 2018
    Location
    New Smyrna Beach, FL
    Posts
    10

    Re: Rapid drop in FC after adding chemicals

    Thanks. It might just be coincidence. Very strange timing for it to happen which is what raised by concern.

    8,000 gal, plaster, PlusHP 3/4hp pump, Jandy CS100 sqft cartridge filter, Jandy AquaPure ei SWG

  6. Back To Top    #6

    Join Date
    Aug 2018
    Location
    New Smyrna Beach, FL
    Posts
    10

    Re: Rapid drop in FC after adding chemicals

    Update:. I had to go out of town for a few days, so being afraid of losing too much chlorine, I added two cups of 10.5% bleach which should have brought the chlorine up 2 ppm to 7.5. Well, at last check, I was at 10 ppm with SWG off.

    Something must've interfered with the chlorine testing initially after adding the chemicals even after several hours of waiting.



    8,000 gal, plaster, PlusHP 3/4hp pump, Jandy CS100 sqft cartridge filter, Jandy AquaPure ei SWG

Posting Permissions

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