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Thread: Found Algae today all over the bottom - Need advice

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    Found Algae today all over the bottom - Need advice

    Hey guys, took my solar cover off after being on for 2 days and found algae all over the bottom of the pool. NOW I know it's my fault due to my negligence the last 2 days, I wasn't able to test and add bleach daily like normal.
    So.. after removing the cover and vacuuming the pool, I tested the water and here are my results.

    FC - 5.5
    CC - 0.5
    PH - 7.8
    TA - 200
    CYA - 60

    I'm confused as to why there is algae if FC is at 5.5
    Should I bring the water to shock level which is 24 for CYA of 60? Or is there anything else I need to adjust?

    Thanks!
    Tim
    17x33 inground rectangle, 20,000 Gals. Vinyl liner. Hayward S200 Filter.

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    Mod Squad YippeeSkippy's Avatar
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    Re: Found Algae today all over the bottom - Need advice

    How are you testing? Which kit are you using?

    I would drop your pH to 7.2 now, because once you get into high chlorine territory the pH test becomes inaccurate at pH >10 ppm. Then follow the SLAM procedure exactly... Pool School - SLAM - Shock Level And Maintain

    Holler back with any questions or other issues
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    Re: Found Algae today all over the bottom - Need advice

    Is the algae yellow/mustard in color (it could look green if against a blue background)? Does it puff up like dust and cloud the pool when you sweep it or is it more sticky and clumpy like green algae? Yellow/mustard algae prefers shade and is more resistant to chlorine than green and black algae. The FC/CYA levels in the Chlorine / CYA Chart are the minimum needed to prevent green and black algae growth, not yellow/mustard algae if algae nutrients (phosphates and nitrates) are plentiful. To keep away yellow/mustard algae would need an FC that is 15% of the CYA level so the normal recommendation is to completely eradicate yellow/mustard algae so that one need not have to maintain the higher level which would use roughly twice as much chlorine (since breakdown from sunlight is proportional to the FC level at the same CYA level).
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
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    Re: Found Algae today all over the bottom - Need advice

    Testing with Taylor K-2006 Kit. The algae does puff up like dust. It looks greenish and I do have a dark liner and there was some areas where is was a little clumpy.
    17x33 inground rectangle, 20,000 Gals. Vinyl liner. Hayward S200 Filter.

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    Re: Found Algae today all over the bottom - Need advice

    If you can carefully collect some of it and take it out of the water and put it on white paper, then you'll be able to tell it's true color.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    Re: Found Algae today all over the bottom - Need advice

    Quote Originally Posted by chem geek View Post
    If you can carefully collect some of it and take it out of the water and put it on white paper, then you'll be able to tell it's true color.
    I'll have to try tomorrow, I've already vacuumed and kids wanted to swim so the water has been all stirred up. I've put some DE in, and after about 25 mins pump pressure was really high. I backwashed and alot of green water came out. Doing another round of DE to help filter. Should I go ahead and bring to shock level?
    17x33 inground rectangle, 20,000 Gals. Vinyl liner. Hayward S200 Filter.

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    Re: Found Algae today all over the bottom - Need advice

    Mmmm. If you think you're filtering it out faster than it's growing (if it's growing), then keep at the filtering, but at some point you'll need to SLAM and normally we'd do that sooner rather than later just to be safe. Is it possible that your cover had a bunch of junk (maybe pollen?) under it and when you put it on it all settled to the bottom of the pool and now you're filtering it out? There's just something strange about this situation. Physical removal of debris or algae is always a good thing. Usually we're doing both in a SLAM -- killing algae with chlorine and filtering the dead algae out.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    Re: Found Algae today all over the bottom - Need advice

    Quote Originally Posted by chem geek View Post
    Mmmm. If you think you're filtering it out faster than it's growing (if it's growing), then keep at the filtering, but at some point you'll need to SLAM and normally we'd do that sooner rather than later just to be safe. Is it possible that your cover had a bunch of junk (maybe pollen?) under it and when you put it on it all settled to the bottom of the pool and now you're filtering it out? There's just something strange about this situation. Physical removal of debris or algae is always a good thing. Usually we're doing both in a SLAM -- killing algae with chlorine and filtering the dead algae out.
    I did another backwash just a few mins. ago. Lots of green water again. I didn't put in anymore DE since it's getting late and I won't be able to monitor the pump pressure. I'm going to go ahead and start SLAM since I'm going to have to at some point. I'm home all day tomorrow so I can keep up with it.

    Thanks for the advice, I'll keep you posted.
    17x33 inground rectangle, 20,000 Gals. Vinyl liner. Hayward S200 Filter.

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