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Thread: Mustard algae not much affected by shock

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    Noorm's Avatar
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    Mustard algae not much affected by shock

    Every day, when I brush, I see small clouds come off the wall, leaving the stains behind. Even though FC is at 33, and Ph at 7.2 it keeps coming back. The stains are kinda scaly looking, and I suspect they will not ever go away.
    Also I'm uncertain about testing with the K-2006 kit:
    The disappearing black spot is sort of imprecise. When I perceive it to be gone, tube is below the 100 line, so I'm guessing about 110. When I test with strips I get 50-100.
    Also for the alkalinity test it says count drops til it turns from green to red, but it only gets to a yellow tint, and after that no change when additional drops are added, if I just base reading on when the green fades to yellow, alkalinity is around 90. Are Taylor's instructions for color change a bit inexact?
    Any insights will be appreciated. I just started taking after the pool when the chemical service I've used for 25 years lost control of the algae.

    Thanks,
    Noorm
    In ground concrete/plaster. Re-plastered 5 years ago Approx 30,000 Gal.
    Hayward 2 speed pump and C3030 cartridge filter. Taylor K-2006 test kit

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    Mod Squad jblizzle's Avatar
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    Re: Mustard algae not much affected by shock

    Welcome to TFP!!!

    First, forget the test strips. Second, with the CYA test below the line, that means the CYA could be VERY high ... it is logarithmic. Try the diluted version of the test described in the Extended Test Instructions.

    BTW, if you CYA is 110ppm (doubtful), then shock level is a FC of 39ppm ... and for mustard (which I would not assume at this point) the FC level is 54ppm This is why your first step should be to replace water to get the CYA to a reasonable level.

    The TA colors get skewed at high FC levels ... that is why you see yellow. This is also described in the link above.
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    Noorm's Avatar
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    Re: Mustard algae not much affected by shock

    Thanks for the help Jason. Can you elaborate on your comment "and for mustard (which I would not assume at this point) "?
    In ground concrete/plaster. Re-plastered 5 years ago Approx 30,000 Gal.
    Hayward 2 speed pump and C3030 cartridge filter. Taylor K-2006 test kit

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    Re: Mustard algae not much affected by shock

    Your description does not really fit the standard mustard algae description. Plus you whole problem is explained by the very high CYA level. So it is very doubtful that you will need to follow the special procedure for getting rid of mustard algae.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Noorm's Avatar
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    Re: Mustard algae not much affected by shock

    Quote Originally Posted by JasonLion View Post
    Your description does not really fit the standard mustard algae description. Plus you whole problem is explained by the very high CYA level. So it is very doubtful that you will need to follow the special procedure for getting rid of mustard algae.
    OK, rechecked CYA with alternative test and got a reading of 60, so I added chlorine to raise ppm to 30. The stuff on the wall looks better , but still seems to be "growing" between brushing.
    If this isn't mustard algae, what else could it be? The FC reading today was 24, so I added 3 gal liquid CL to raise it to about 35.
    Am I on the right track? Also, are the stains on the pool walls gonna require draining and acid wash to remove?
    In ground concrete/plaster. Re-plastered 5 years ago Approx 30,000 Gal.
    Hayward 2 speed pump and C3030 cartridge filter. Taylor K-2006 test kit

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    Re: Mustard algae not much affected by shock

    OK, rechecked CYA with alternative test
    The Taylor CYA test is the most accurate on the market......what alternative did you use?
    Dave S.
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    Noorm's Avatar
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    Re: Mustard algae not much affected by shock

    The Taylor booklet suggested diluting sample with tap water, then doubling the multiplier.
    In ground concrete/plaster. Re-plastered 5 years ago Approx 30,000 Gal.
    Hayward 2 speed pump and C3030 cartridge filter. Taylor K-2006 test kit

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    Mod Squad tim5055's Avatar
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    Re: Mustard algae not much affected by shock

    That is the correct method for checking high CYA. 30ppm FC is still too low for 120 CYA.

    Using THIS CHART because your CYA is above 100 you find your shock level is a whopping 47 (46.7, but who is quibbling over a little)

    The pool service probably used pucks and "shocked" the pool once a week with a powerded shock, thus your current CYA level.

    I assume you have read the directions on SLAMing your pool in the How To section of Pool School.

    The problem with high CYA is the insane amount of chlorine you need to kill algae once it gets a foothold. You may need to do something about the CYA first.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: Mustard algae not much affected by shock

    Quote Originally Posted by tim5055 View Post
    That is the correct method for checking high CYA. 30ppm FC is still too low for 120 CYA.

    Using THIS CHART because your CYA is above 100 you find your shock level is a whopping 47 (46.7, but who is quibbling over a little)

    The pool service probably used pucks and "shocked" the pool once a week with a powerded shock, thus your current CYA level.

    I assume you have read the directions on SLAMing your pool in the How To section of Pool School.

    The problem with high CYA is the insane amount of chlorine you need to kill algae once it gets a foothold. You may need to do something about the CYA first.
    Okay, I see where I failed to read the test correctly. Got the dilution part, but forgot to double the reading, so apparently I am actually at 120 ppm. So now my only solution is to start replacing water, right? Any figures on how much water needs to be replaced to cut the CYA in half? With the drought we are experiencing, that may be a problem. (Dang, I've used up most of the CYA reagent in the test kit.)
    Actually my pool is crystal clear, and the stuff is not forming nearly as much on the sides, but it is still there. Also, I'm still wondering if the staining will ever go away. No matter how hard and long I go at it with the wire brush, the underlying splotchy stains remain.
    In ground concrete/plaster. Re-plastered 5 years ago Approx 30,000 Gal.
    Hayward 2 speed pump and C3030 cartridge filter. Taylor K-2006 test kit

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    Mod Squad kimkats's Avatar
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    Re: Mustard algae not much affected by shock

    Replace some of your water. use this link to see how much. http://www.troublefreepool.com/calc.html

    Once you have your cys down to 50 or so you will have a much easier time killing what is causing the yellow.

    Kim
    TFP Moderator 33x52 round AG 25,600 gals Sand Filter 1.5hp Pump - 2 Speed, SLAM, Pool School, Recommended Levels, Recommended Chemicals, Pool Math, Chlorine/CYA Chart, TF-100 Test Kit

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    Re: Mustard algae not much affected by shock

    Cya reduction is linear to water replacement. 50% drain and refill would give you the same reduction. The Taylor 2006 is a wonderful kit, but this reagent shortcoming is why we suggest the TF100 kit like we do. Same reagents but in higher quantity.
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    Re: Mustard algae not much affected by shock

    Quote Originally Posted by Patrick_B View Post
    Cya reduction is linear to water replacement. 50% drain and refill would give you the same reduction. The Taylor 2006 is a wonderful kit, but this reagent shortcoming is why we suggest the TF100 kit like we do. Same reagents but in higher quantity.
    Thanks. I now must decide whether to go against my water company's restrictions on drain and fill.
    In ground concrete/plaster. Re-plastered 5 years ago Approx 30,000 Gal.
    Hayward 2 speed pump and C3030 cartridge filter. Taylor K-2006 test kit

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    Mod Squad tim5055's Avatar
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    Re: Mustard algae not much affected by shock

    Before you go out and get the water police all riled up, check out the ongoing threads on the new bio-active cya reducer on the market. Several folks an the board are testing it so we don't have an opinion yet, but it may be something to look at. The current folks were starting at CYA levels in the 4 - 600 range. It seem sslow going for them, but you may be a good candidate for a more "normal" high CYA test.

    Just and idea/option.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Noorm's Avatar
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    Re: Mustard algae not much affected by shock

    Quote Originally Posted by tim5055 View Post
    Before you go out and get the water police all riled up, check out the ongoing threads on the new bio-active cya reducer on the market. Several folks an the board are testing it so we don't have an opinion yet, but it may be something to look at. The current folks were starting at CYA levels in the 4 - 600 range. It seem sslow going for them, but you may be a good candidate for a more "normal" high CYA test.

    Just and idea/option.
    Thanks, looks promising. My concern is that I have to lower FC before using the BioACtive product, and how long will it have to remain reduced, during which the algae will proliferate.
    In ground concrete/plaster. Re-plastered 5 years ago Approx 30,000 Gal.
    Hayward 2 speed pump and C3030 cartridge filter. Taylor K-2006 test kit

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