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Thread: Mustard Algae

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    Mustard Algae

    Good afternoon! I am new to TFP, but have been reading the forum for a few months. I finally signed up after battling mustard algae that won't seem to go away.

    I had a severe mustard algae outbreak last September before I realized that the "dirt" on the bottom of my pool was a type of algae, as I am a new in-ground vinyl pool owner. I got rid of it by using Mustard eliminator (99% sodium bromide) and vacuuming to waste.

    I maintained the pool all winter with no problems. Now since March 15th, I have had three separate mustard algae blooms, although I caught these very early. I again used the Mustard Eliminator, but was able to get rid of the algae using only the sand filter and backwashing once since I caught it so early.

    My question is why is this algae coming back every two or three weeks? I maintain FC between 1-2 and have had no CC's until now (.5), and also use a nonmetallic algaecide weekly. Is sodium bromide the way to go?

    All testing done using the TF 100 kit that I purchased after reading this forum.

    Please help! Thanks!

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    Mod Squad JVTrain's Avatar
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    Re: Mustard Algae

    How much FC you need to maintain is highly dependent on your CYA (stabilizer) level. Your CYA level determines the minimum FC you must maintain. Post your full test results here. Check out the CYA/Chlorine chart in my signature for your needed FC levels. If you believe it's mustard algae, you need to complete the SLAM procedure (also in my signature) then perform the mustard algae FC increase once you pass the SLAM criteria. The mustard shock level is found here: Chlorine/CYA Chart
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: Mustard Algae

    FC - 4
    CC- 0
    PH - 7.5
    CYA - 40

    As of today...so the slam procedure is recommended for Mustard Algae? I will do that....the pool store guy told me chlorine wouldn't kill mustard algae without the Mustard Eliminator. Go figure!
    Thanks!

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    duraleigh's Avatar
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    Re: Mustard Algae

    the pool store guy told me chlorine wouldn't kill mustard algae without the Mustard Eliminator.
    That is so totally bogus it infuriates me that they dish out advice which is not only worthless but causes harm. Please stay out of the pool store.

    Yes, bring your FC up to SLAM value and hold it there until any sign of the mustard algae is gone. That's be about 16 ppm, I think.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Mod Squad JVTrain's Avatar
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    Re: Mustard Algae

    The mustard eliminator product is a bromine product as you realize from the label. If you had a severe elevated CYA problem (150+) and for some reason could not drain the pool to reduce it, this product might be an option. Bromine's strength is not buffered by the presence of CYA. So... it could be used in that situation to kill the algae and get the pool by until CYA can be reduced. You would have to somehow use that product like chlorine to perform a modified SLAM. But... there are no guidelines or kill rates or recommended levels to maintain bromine concentration on TFP for this type of procedure. Bromine also has no protection from the sun, so much of your money would go down the drain and lost to sunlight. Another reason why bromine is not recommended for outdoor pools. Once you use that product, you will have residual bromide in your pool for quite some time. When bromine oxidizes organics, you end up with bromide. When you add chlorine to the pool, bromide is converted back into bromine. For a while, you'll essentially have a chlorine/bromine hybrid pool until the bromide breaks down, which it will do slowly.

    Long story short, with low CYA and not having a water restriction, it's cheaper and simpler to just use chlorine and the SLAM procedure, followed by the elevated mustard shock level for FC.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: Mustard Algae

    Thanks to both! I really appreciate it!

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