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Thread: Algae keeps showing up

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    Join Date
    May 2015

    Algae keeps showing up

    Hi, I need advice. Used a Taylor 6000 kit last night and here is what it came up with: FC 2.5 Ph 7.4 Those were the two tests we had been doing and thought the chemistry was ok, but the constant issue with algae made us get the
    more complete test kit to do further testing. Alkalinity came in at 175 and Calcium is ungodly at 750 and the CYA was off the chart. Even doing the test over again with the 1/2 pool water and 1/2 tap, it still would not even register
    close to 100. The black dot was hidden by the milky water way down about 1/2 inch up on the vial (so far below the 100 that I have no clue what the reading would be)
    The kit did not have a way to test phosphates. I have a feeling that is part of our problem also because we fight oak leaves and oak blooms really bad in the fall and the spring. I have been reading about CYA and Calcium and realize that the Leslies pucks we have been using are elevating those while not allowing the chlorine to do it's job with the Algae. We have been brushing the pool and backwashing weekly to no avail. It keeps coming back. What should we do?
    We are also on well water so our water is not going to be the best. It is very hard water (Texas hill country) and probably alkaline so even putting fresh water in will not be an automatic fix.
    Help... Please...

  2. Back To Top    #2
    Smykowski's Avatar
    Join Date
    Sep 2011
    Gurnee, IL (North Suburban Chi-town)

    Re: Algae keeps showing up

    Welcome to the forum!

    Phosphates have nothing to do with your problem (I don't know what my phosphate level is and I don't care).

    The issue is that your CYA is too high and your FC is too low, so it's time to SLAM the pool. Take a look at the article in Pool School. Also, click on the link in my signature. Let us know what questions you have after reading.
    33' round, 23,000 gal AG vinyl , 1HP 2spd PowerFlo Matrix downsized with 3/4HP impeller (X2), Hayward S180T 150# sand filter (X2), Hayward H250 NG heater Pool Store year 1 - $850 for 2 months; Pool Store year 2 - $440 for 2 months, TFPC year 1 - $170 for 4 months; TFPC year 2 - $95 for 4.5 months
    The most important article on this site - The ABCs of Pool Water Chemistry

  3. Back To Top    #3
    Divin Dave's Avatar
    Join Date
    Oct 2013
    Longview, Texas

    Re: Algae keeps showing up

    Hi Mkelley,

    The root cause of the problem is your sky high CYA.

    There is a definite and undeniable relationship between FC and CYA. If CYA is too high, the FC cannot overcome its buffering effects and the result is that algae blooms. You can use all of the algaecide and phosphate remover you want, but it wont solve the problem. Algae will just keeps coming back, and back, and back. That is what's happening to you.

    Unfortunately the only way to remedy the situation is to drain enough water from the pool to get rid of the CYA.

    We dont recommend draining more than 1/2 water at a time because of the hydrostatic pressure issue. Due to your location, hydrostatic pressure may not be an issue, so the decision to drain more than 1/2 if you choose to do so has to be made by you.

    If you only drain 1/2 at a time, wIth CYA off the charts, it will likely be necessary to do a series of drain and refill. I understand the water well issue and the kind of problem that might be.

    If I were you, I would consider having new water tanked in. No clue what that might cost though, so just throwing it out there.
    Anohter possible option is to have Reverse Osmosis performed on your pool water. This may be a more reasonable option, depending of course the availability of someone to do it. RO services are available from Aquatique Pool Care out of Austin. Again, no idea of what that might cost.

    I have no relationship at all with Aquatique. I googled it and found them.

    Once you have your CYA in check, you can SLAM (similar to shock but different), and then maintain your CYA/FC ratio corretly and diligently and you'll never have algae again.
    Divin Dave,
    IG Vinyl, 15' x 30', 3 1/2' - 6' deep, Oval, ~15K gal, Intelliclor IC40, Intelliflo VS pump, Clean and Clear 420 Filter, auto-fill-disabled, Retrofit LED Color Light, Dolphin Nautilus Robot, TF100 Test Kit, Taylor K1766 Salt Test Kit, Tftestkit Pressure Gauge. Experience- it's what's learned just after you needed it most !!

  4. Back To Top    #4
    Mod Squad pooldv's Avatar
    Join Date
    Aug 2012
    DFW, TX

    Re: Algae keeps showing up

    Welcome to TFP.

    The #1 most important element of pool maintenance is maintain chlorine level. Chlorine level must never drop below the minimum level for your CYA based on this Chlorine CYA Chart. It only goes to 100 because really even 100 is too high. For 100 CYA the minimum chlorine level is 7 and the target is 12.

    You will need to do a series of drain and refills to lower the CYA level.

    Please provide the following information so we can have a full picture, What we need to know to answer your questions.

    Here are some introductory articles in Pool School to start reviewing.
    TFPC for Beginners
    ABC's of Pool Water Chemistry
    TFP Moderator
    If TFP helped you or saved you money - Become a TFP Supporter! <--Click here
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  5. Back To Top    #5
    Mod Squad YippeeSkippy's Avatar
    Join Date
    Jan 2012
    'burbs of Augusta, Georgia

    Re: Algae keeps showing up

    Test Kit! You need a RELIABLE test kit such as the TF-100 or the Taylor 2006 *that contains the FAS-DPD chlorine test*
    Once you have the test kit, you can perform a proper SLAM procedure to rid your pool of the algae cooties.
    The CYA needs to be lowered, so that your chlorine requirement is more reasonable.
    You CAN do this!!
    Maddie :) 12K Fiberglass IG, Infinity 4000 automatic cover, SWCG, Hayward Sand Filter, Hayward 1.5 Pump, Doheny Discovery Robot, Savi Melody LED pool lights, outdoor speakers and other assorted doo-dads. Sundance Altamar Hot Tub.
    Our pool build--> Our Pool Solved Our Sloping Yard Skippy's Cheap Pool Cooler -->Skippy's New Fountain

  6. Back To Top    #6
    Casey's Avatar
    Join Date
    Apr 2007
    SW PA

    Re: Algae keeps showing up

    You've gotten solid advice. Your first plan of action should be a series of drain/refills and, ordering a TF100 from
    I'd bet you my bikini you'll never get TFP water from a pool store!

    24' Sharkline Venture De Filter

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