Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 5 of 5

Thread: High chlorine demand

  1. Back To Top    #1

    Join Date
    Sep 2010
    Location
    Tampa, FL
    Posts
    14

    High chlorine demand

    Is high chlorine demand an indication that I need to shock my pool?

    Every since switching to BBB a week ago my water is crystal clear and I don't accumulate nearly as much "junk" at the bottom of the pool. However, my chlorine demand is 4-5ppm per day. Not sure if this is within normal limits, or if I should think about shocking. CC is less than .5ppm, the water is clear and OCLT is 1-1.5ppm.

    Thanks!

    Doji
    15,000 gallon outdoor in-ground plaster pool
    Sand filter flow rate 62 GPM
    3/4hp pump

  2. Back To Top    #2

    Join Date
    Aug 2010
    Location
    Boston, MA
    Posts
    176

    Re: High chlorine demand

    OCLT more than 1 ppm suggests a need to shock, as it demonstrates that there are organics in the pool which the chlorine is fighting.
    20k gallon IGP
    Plaster over gunite
    3/4 hp Hayward pump
    Purex Triton DE filter
    TF100 test kit w/ speedstir

  3. Back To Top    #3

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,083

    Re: High chlorine demand

    You are calling it high chlorine demand but seem to imply that it is nothing out of the ordinary and has been going on for some time. Help us understand if it's a recent trend or not.

    Secondly, you need to tell us your CYA which is all-important to chlorine consumption.

    Normally, I would suggest shocking also but your OCLT results are VERY borderline so the answers to the above questions give us a much clearer picture.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  4. Back To Top    #4

    Join Date
    Sep 2010
    Location
    Tampa, FL
    Posts
    14

    Re: High chlorine demand

    Sorry. I guess that's the point of the question. Not sure what high is.

    CYA is 60. I've been raising FC to 9 at night, it's 7.5-8.0ish in the morning and back at 4-5 by evening.

    Only started BBB about a week ago so no idea what was going on before that.

    I've probably never technically shocked the pool. Just followed the pool store instructions of dumping 2.5 gals of chlorine per week.

    The water has never looked better.

    Thanks!
    15,000 gallon outdoor in-ground plaster pool
    Sand filter flow rate 62 GPM
    3/4hp pump

  5. Back To Top    #5

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,083

    Re: High chlorine demand

    I'm sorry I missed that "one week" in your first post. Based on that and your CYA value, I would shock the pool.

    Once you complete the process, I think your FC consumption will drop noticeably.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

Posting Permissions

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