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Thread: High Phosphates

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    Join Date
    Aug 2016
    Orlando, FL

    High Phosphates


    Our pool is only four months old and as of the last few weeks it seems we have been experiencing high phosphates every time we have the water tested. The water is clear and no algae that we can tell. I read many articles on here that say high phosphates aren't a concern if the FC and CYA are in check but it seems odd that it wasn't an issue before and now it is. Any thoughts?
    TC: 5
    FC: 5
    PH: 8 (It is a newly plastered pool so we are adding acid every few days as needed to bring this down)
    TA: 105
    CH: 420
    CYA: 90
    SWG: 3700
    Phosphates: 2500

  2. Back To Top    #2
    Mod Squad mknauss's Avatar
    Join Date
    May 2014
    Laughlin, NV

    Re: High Phosphates

    Do not go to the Pool Store for testing. Do your own. No need to consider phosphates as long as you maintain your FC levels appropriate to your CYA.
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  3. Back To Top    #3
    Swampwoman's Avatar
    Join Date
    Apr 2012
    Grand Rapids, MI

    Re: High Phosphates

    Charid, maintaining to FC/CYA Chart will effectively avoid algae, so its true it doesn't matter a great deal...but like most things, there's a tiny grain of truth to the poolstore hype. The tiny grain of truth is that phosphate is in fact a nutrient to algae.

    While the TFP way advocates simplicity above all else, ( eg you dont need phosphate remover so don't add it) there are those who will use products such as Seaclear phosphate remover periodically to prevent a major build up.

    2500 ppb is not to my mind very high. As a well water pool owner who has to use sequestrant to avoid iron staining, mine have built up to more than 10x that and I've never had an algae outbreak.

    Sequestrant breaks down over time, via chlorine oxidation, for example, into phosphates, both in municipal water systems that use it to prevent corrosion, and in pools where owners or techs apply a stain and scale treatment that is phosphonic acid based.

    In my case, since I trucked in fresh water last year during a liner change, I'm of a mind for annual or seasonal removal just to avoid the kind of build up I had before. But your mileage may vary. Its a personal choice, and IMHO, not critical, particularly at those levels. I went years with no harm
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    Mod Squad YippeeSkippy's Avatar
    Join Date
    Jan 2012
    'burbs of Augusta, Georgia

    Re: High Phosphates

    If Leslie's Pool Store can't find anything bigger to sell you the cure for, they pull out the Phosphate Scare Card and scare you about phosphates.

    Ignore them. In fact, stop going to a pool store for testing. The only way to get good testing you can trust is to do it yourself.

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  5. Back To Top    #5

    In the Industry

    Join Date
    Apr 2017

    Re: High Phosphates

    Phosphates are in fact algae food, no algae, who cares about the food. Algae enters your pool every day, wind, rain, run off, it happens. If phosphates are present that algae can grow quicker. Any reading over 3000 ppb is considered minimally high.


    one bottle of phosphate remover will rarely remove more than 300 ppb, more often the results only show a drop of around 150-200 ppb. So just how much and how often you will have to remove it is anyone's guess. Pool stores love selling it. Every tests they do shows it. Anyone who follows the cya/Chlorine ratio will never be able to point a finger at phosphates.

  6. Back To Top    #6
    Mod Squad tim5055's Avatar
    Join Date
    May 2014
    Franklin, NC

    Re: High Phosphates

    What you can't see behind the counter at the pool store:

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