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

Thread: Is it algae?

  1. Back To Top    #1
    Guest

    Is it algae?

    I have several dark patches on the bottom of the deep end of my in-ground pool. I noticed them last year, and they were still there this spring.

    I am meticulous about proper levels and cleaning. However last year, while on vacation, the chlorine level dropped to 0 for a few days.

    I have brushed and shocked (to 20). I tried rubbing a chlorine puck on the stains, with no effect at all. I treated with polyquat a few days ago. Could these be stains instead of algae growth?

    Thanks for any help!

    Levels and info:
    TC: 7
    FC: 7
    pH: 7.4
    TA: 90
    CYA: 30
    CH: 180
    Borate: 30
    Copper: 0
    Liner: vinyl
    17,000 gallons
    DE filtering
    Pump on 14 hours a day since May 15


  2. Back To Top    #2

    In the Industry

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

    Re: Is it algae?

    Welcome to the forum. Hold the puck on the stain for a minute or so and see if it fades or removes it.

    If that fails again, crush up some cheap vitamin C tablets into a sock and hold thatsock on the stain for about tree minutes or so. See if that lightens or removes it.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  3. Back To Top    #3
    Guest

    Re: Is it algae?

    I tried both 3" puck and Vitamin C. They both seemed to fade the spots. It got dark, so I'll try some more tomorrow.

  4. Back To Top    #4
    Guest

    Re: Is it algae?

    OK, putting chlorine pucks on the spots for several minutes fades some spots, and completely clears them. I spent several hours doing that, along with brushing, and the spots are 80% gone, and many have disappeared!

  5. Back To Top    #5

    In the Industry

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

    Re: Is it algae?

    Well, it sounds like you are on your way to success. Keeping your FC right about where you have it @ 7ppm or maybe even 10ppm will likely make the stains disappear faster but may still take a few days to clear them altogether.

    Chlorine is the best friend of clean pools. Keep it at 3-5ppm even after your stains are completely gone.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  6. Back To Top    #6
    Guest

    Re: Is it algae?

    All the stains are gone! The key for me was to put 3" chlorine pucks on the spots (I used around 20 at a time) for 5-10 minutes, brushing with a stiff hand brush, more pucks, more brushing, etc. Then keep FC at 20 (CYA=20) for 3 days. Thanks for your help!

Posting Permissions

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