Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 2 of 2

Thread: FC loss after vacuum

  1. Back To Top    #1

    Join Date
    May 2009
    Charlotte, NC

    FC loss after vacuum

    Hi guys

    I am at the final push against algae. My chlorine usage each day has progressively dropped to about 30-40% a day at 50% CYA and almost have a zero Fc drop at night.

    One thing I noticed while testing in the last few days: Every time I vacuumed the floor, there is a slight increase in Cl usage, like 0.5 FC increase for about 2-3 hours.

    Is this due to
    1. algae growth during the day (no swimming yet), or
    2. Biofilm being disrupted, or
    3. Something in the filter or vacuum brush or
    4. Is Cl not as effective at 4' depth

    I have been vacuuming for a week, and so it is hard to believe there is still a biofilm. My Cl levels range from normal to shock ( about 8.5-14) during the day and (13 to 15) at night for a week. I also do have the pool turn somewhat less clear after vacuuming, that reverses in a few hours. My nos: FC 13, CC <0.5, PH 7.2, Alk: 100, CH 150, CYA 50.

    Above Ground 14.2 K Gallon, vinyl, Baquapure sand filter, 2.5 HP pump, K-2006 test kit

  2. Back To Top    #2
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: FC loss after vacuum

    Organic debris that falls to the bottom can get buried under subsequent layers of debris before chlorine has time to oxidize it. Vacuuming can expose the buried debris to the chlorine in the pool, which then uses up some of the chlorine.
    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

Posting Permissions

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