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

Thread: How is this even possible???

  1. Back To Top    #1

    Join Date
    Jul 2012
    Location
    California Central Coast
    Posts
    74

    How is this even possible???

    Sorry to keep bothering everyone, but I am about to go crazy. As mentioned in my other posts, I am shocking my pool due to one reason: an overnight FCL of 1.5. Everything else is fine. But as I mentioned also, when I started shocking, I got a 4.5 drop in FC overnight. I thought that was weird enough, but today I have been pampering the pool trying to keep it at or above shock level, and now things are defying logic. I added bleach this morning and brought FC up to 22 (Shock level is 20 for my CYA). Two hours later, I was at 19. Okay, extreme sunlight loss, I assumed. I bumped it back up to 23 this time. ONE hour later I was at 19 again! Weird enough? Not yet: I bumped it back to 23, let it mix for about 30 minutes, and then decided to bump it higher so that I didn't fall below 20 again. I added half a gallon more bleach, waited 40 minutes; and I was at 22! Adding bleach brought it down! I thought maybe my titrating reagent was bad. I had another bottle, luckily, and retested; same result. I've tried getting water samples from different areas; same result. What the heck is going on!?
    Test Kit: Taylor K-2006
    Pool:In ground/Pebble/16,000 gal/Cartridge Filter/Pool Built appr. 1995-2000

  2. Back To Top    #2

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,084

    Re: How is this even possible???

    You should keep all your posts under one thread for continuity and so others can read your whole story.

    That said, what you report is absolutely normal. Two things consume chlorine......organics in your pool and sunlight. Some combination of those is consuming your chlorine. Why does that seem unusual to you?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  3. Back To Top    #3

    Join Date
    Jul 2012
    Location
    California Central Coast
    Posts
    74

    Re: How is this even possible???

    Sorry for the multiple posts. I will keep them under one thread next time. It seems unusual because under normal FC levels I was losing 3ppm chlorine all day long, and 1.5 overnight, and then suddenly when I start shocking I am losing 3-5 ppm in a matter of 1 hour and 4 ppm overnight. Why would the loss increase so wildly? And how could adding half a gallon of bleach result in a 1ppm LOSS in 40 minutes?

    Is it perhaps that at shock levels the chlorine is getting used at a MUCH more rapid pace?
    Test Kit: Taylor K-2006
    Pool:In ground/Pebble/16,000 gal/Cartridge Filter/Pool Built appr. 1995-2000

  4. Back To Top    #4
    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    Location
    SW Indiana
    Posts
    9,089

    Re: How is this even possible???

    Yes, chlorine is depleted more rapidly by UV at higher levels.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

  5. Back To Top    #5
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: How is this even possible???

    I think part of what you see seeing is that with as given CYA level, you will lose a % of your FC to the sun. Since you are at higher FC values, that % is a higher FC ppm. Losing 3 out of 20 is a lot lower % than out of 6.

    This may not be exactly correct, but the basic idea I think.

    Posted from my Droid with Tapatalk ... sorry if my response is short
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  6. Back To Top    #6

    Join Date
    Jul 2012
    Location
    California Central Coast
    Posts
    74

    Re: How is this even possible???

    Okay, that totally makes more sense. Thank you all. I thought I was going crazy!
    Test Kit: Taylor K-2006
    Pool:In ground/Pebble/16,000 gal/Cartridge Filter/Pool Built appr. 1995-2000

Posting Permissions

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