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Thread: Red Algae?

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    Red Algae?

    Towards the end of last pool season, our pool kept getting something reddish pink in certain areas.(ladder, light, return jets) The pool store said they had no idea what it was to begin with, but told us to shock and brush and it should disappear. It would but would reappear a few days later. They said our numbers were all in balance. Has anyone run across this?
    25,000 gal. I/G Vinyl Liner Pool; Pentair IC40 SWCG; 3/4 hp Hayward Pump with 244t Hayward Sand Filter

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    frustratedpoolmom's Avatar
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    Re: Red Algae?

    Yes, and it means that in all likelyhood you were not properly chlorinating the pool. Often the pool stores determination of "good" or "balanced" is not correct at all... some mean well but they just don't understand the pool chemistry side of things.

    Your FC level is determined by your CYA level. Refer to the chart (link in my sig). If you maintain the proper FC levels according to the chart, your pool should be trouble free. Edit: Now that you are going to be using an SWG - see "Water Balance for SWGs" in Pool School.

    Can I guess that you added a one time application of shock, brushed - and then allowed the FC to drop back down (to a range that's probably too low for your CYA level) which allowed the algae to return. (What level do you typically keep the CYA at?) How often do you run the pump? What was your typical daily FC level? When you shocked, what product did you use?

    You have to use an FAS-DPD test to confirm that anything organic is fully dead (see How to do an Overnight FC loss Test in Pool School) and "How to Shock your Pool". Then you maintain the appropriate chlorine level to prevent anything from coming back.

    Hope this helps.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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    JasonLion's Avatar
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    Re: Red Algae?

    Quote Originally Posted by sdjcherring
    They said our numbers were all in balance.
    You won't believe how often we hear this, and it is almost never true. If you have a full set of water test results, either from last year or right now, we can give you much more specific advice.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: Red Algae?

    Here are a set of numbers i found from last year.
    FC- 1.0
    TC-1.0
    TA- 81
    PH-7.2
    CALCIUM- 70
    CYA- 40
    TDS-200
    The only thing they recommended was to shock.

    Thanks
    25,000 gal. I/G Vinyl Liner Pool; Pentair IC40 SWCG; 3/4 hp Hayward Pump with 244t Hayward Sand Filter

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    Ohm_Boy's Avatar
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    Re: Red Algae?

    Yeah, with a CYA level of 40, you should have been shooting for a FC level of around 5. You would have needed to shock to about 16, and I'm betting that you can't measure that, unless you have a FAS-DPD kit, and few pool stores will use or recommend that. No surprise that you had algae.
    [center:1kpalu48]Helpful Links: Pool School | CYA/Chlorine Chart | Pool Calculator[/center:1kpalu48]

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    JasonLion's Avatar
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    Re: Red Algae?

    Yep, what Ohm_Boy said. With CYA at 40, FC should be between 3 and 7 when you don't have a problem. And to reliably get rid of a problem FC should be 15 to 17 for a day or two minimum, not just one application of chlorine.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: Red Algae?

    Thanks,
    Also, along with the reddish/ pink algae, occasionally when i would brush around the lights and jets, a dull, white slimy ? would brush off. Is this algae also?
    25,000 gal. I/G Vinyl Liner Pool; Pentair IC40 SWCG; 3/4 hp Hayward Pump with 244t Hayward Sand Filter

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    JasonLion's Avatar
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    Re: Red Algae?

    Most "red algae" is actually a bacteria and the white stuff is probably a fungus, but the treatment is the same in any case: more chlorine and brushing.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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