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

Thread: Black spots inside skimmer

  1. Back To Top    #1

    Black spots inside skimmer

    2 month old pool. 15k gallons. VS pump. SWG. Oversized sand filter. testing and brushing twice a week.

    I have noticed round black spots at the water level on the grout at the back of my skimmers. It brushes away easily but always comes back. No other spots anywhere. Sure looks like algae to me. Should I be concerned? How do I eliminate it once and for all?
    FC never lower than 3. Would prefer 5-6. Getting used to SWG. just added borax today.
    Any thoughts?


  2. Back To Top    #2
    frogabog's Avatar
    Join Date
    Jul 2010
    Portland, Oregon

    Re: Black spots inside skimmer

    A full set of test results would tell us more.

    What test kit do you use?

    What happens to the spots when you wipe/brush at them? Does an application of bleach clear them?

    Have you used any trichlor tablets recently? They make my skimmer get a black ring.
    Where kids swim in 54 degree water, turn blue, and giggle happily cuz they got a POOL!
    Year 3 BBB -15' x 48" Intex Metal Frame - Was using (2) 1000gph Intex cartridge filters (see Full time pumping Intex). 2012, converted to 1600gph and sand filter+SWG = Sand filter love affair!
    Don't waste time and energy looking for a better value on test kits, the TF100 is the best deal around. I did the looking and spent the extra money, but you don't have to make the same mistake. Just go here: TFTestkits. I use Pool Calculator for min/max, and shocking chlorine levels.

Posting Permissions

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