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Thread: 3 days of shock, still green...

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    3 days of shock, still green...

    Pretty sure I have/got mustard algae. I started noticing some orange/brown debris on the bottom of the pool and later on the walls. When I brushed it, it had the appearance of dirt in the water, but would not vacuum up. Later (while waiting on my DPD-FAS kit to arrive) the water turned completely green.

    Starting my algae killing chore this last weekend. Started with CYA at 30. Lowered PH to around 7.0. Started adding bleach, added more bleach, added more bleach, added more bleach. Finally got the FC to 19. Held it there for 1 day, while brushing the pool often. Have maintained the FC in the 12-13 range for the last two days with no visible improvement in water color/clarity. Overnight FC loss will be in the 1-2 ppm range. Have been running the pump 24/7. Sand filter started at 17 psi (with brand new gage) after 2 days it's only at 19 psi.

    Any ideas of why my pool is not clearing up? I have not observed this "milky white"/"gray" color that is reported here. Thanks in advance for the help.

    48,200 gallon, sand filter

  2. Back To Top    #2
    harleysilo's Avatar
    Join Date
    Mar 2012
    North Georgia

    Re: 3 days of shock, still green...


    Please fill out your signature line with your pools details so we can easily reference them.

    You have a large pool, how big is your sand filter?

    3 days is not really that long for a green pool, and you are continuing to show overnight losses so you are still fighting hard.

    What is the source of your fill water? Do you, have you had metals in your water? Do you, have you used a lot of algaecide in your water?
    18'x43' Sport Pool
    19,000 Gallons Vinyl Liner 3'-3.5'-4'
    SWCG and D.E. Filter
    Test Kits - Pool Calculator - Chlorine/CYA Chart - Pool School

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  3. Back To Top    #3
    Richard320's Avatar
    Join Date
    Jan 2010
    San Dimas, CA (LA County)

    Re: 3 days of shock, still green...


    I can think of a couple likely villains.

    1) The CYA could be higher than you think. You might want to redo the test to be sure. Take a reading, pour the sample back in the mixing bottle, shake, take another reading, pour it back..... Do it as many times as it takes until you start getting consistent readings - within 10 ppm - and use the highest of them as the level.
    2) Sand filters tend to be slow at filtering after the SLAM. Which is why there's even a little note mentioning adding some DE to the filter. See if you can't be a beg a little from a neighbor with a DE filter, you only need a few cups. If it helps, you'll notice it withing hours - your filter pressure will go up dramatically as it loads up with dead algae.

    Hope this helps.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    SW Indiana

    Re: 3 days of shock, still green...

    Usually the first thing you'll observe is a subtle shift from the yellow side of green toward the blue side of green. It's not dramatic, but it always happens. Color change comes from chemistry, but clarity depends on filtration.
    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

    Re: 3 days of shock, still green...

    Thanks for the replys!

    Yes, the pool is very large, 58' x 20' rectangular. The water is from a well with pretty high alkalinity. I am a new pool owner and I have personally never put algaecide in the water although I can't say for certain if the previous owner used it.

    I'll double check the CYA when I get home and add my pool details to my signature.

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