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Thread: Black algae problem. Help

  1. Back To Top    #1

    Join Date
    Aug 2013
    Stockton, Ca.

    Black algae problem. Help

    I have black algae growing on my pebble tec and the tile and the white floats connected to my pool sweep.
    My readings are TC 9.5ppm
    TA 100
    CH 40
    CYA 100

    Water is clear, no smell. I initially had it in a few spots. I put black algae killer in it over a month and scrubbed the 10 spots i could see it for over hour off and on. I thought it was gone but now I'm noticing it all over probably 200 spots all over. Too much to scrub off. I'm thinking I need to drain pool and have someone come in with acid and scrub off. Help
    Chris M. 20k, inground, defilter, pebbletek, 1hp motor,Tiger Shark QC, TF-100, switched to liquid chlorine 3 years ago LOOOOVVVVEEEE it!

  2. Back To Top    #2
    Butterfly's Avatar
    Join Date
    May 2007
    South Carolina

    Re: Black algae problem. Help

    What test kit are you using?

    CYA tests read 100 and anything higher than 100, as 100 So, you should do the 50/50 dilution test for CYA to confirm that it is 100, or maybe even higher. Regardless, you will need to start with some water replacement to get the CYA down to something reasonable, like 50.

    Having black algae does not mean that you have to empty the pool. You can get rid of BA if you follow the SLAM process in Pool School and scrub the BA with an algae brush. You can also rub trichlor tab directly on spots to help kill. The BA has to be scrubbed open (remove outer layer) w/algae brush first to allow the chlorine in for the kill.

    Post back with any questions. Someone will be around to help.
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

    ~ One should not use a sledge hammer to swat a mosquito. ~

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