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Thread: Mustard Algae?

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    Mustard Algae?

    Hello everyone. I have been a lurker here and over at PF for a few years. Never really had a problem, but I come here often to learn. Right now I think I am battling mustard algae and I don't know how to beat it. I have tried several times to get rid of it to no avail. I believe I had mustard algae last year, but couldn't get rid of it. I am determined to do it this time. Here are my current numbers taken with K-2006 test kit.
    FC - 19
    CC - .5
    PH - 7.3 (taken 1 1/2 weeks ago before I started shocking)
    CYA - 30-40
    TA - 160
    Calcium - 200
    I started shocking the pool on about June 30 to 18ppm. I bring it back to shock levels 3 times a day. Needless to say I've used a lot of bleach. The water is sparking clean, I just get gatherings of brown/yellowing "dust" in the divets of the pool every day. I have been vacuuming and brushing the sides once a day. I keep the solar cover on at night so we can try to enjoy what little summer we are having (current temp is 80). I checked the levels last night at about 10pm, and my FC was 18.5. At 6am it was down to 14. I am at my wits end with this stuff and don't know what to do. To make matters worse, we are leaving town on Sat. morning and not returning until Wed. evening. I thought when I started this I would have it well under hand by now. It seemed like there was less algae in the pool after the first few days, but then we had a thunderstorm on Monday and I'm right back where I started. I even checked the levels after the storm and brought it right back up to where it was supposed to be.
    Any advise would be appreciated. I am thinking of trying the borates thing. Any suggestions?
    Thanks!
    28' AG, 17000 gal., sand filter

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    TizMe's Avatar
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    Re: Mustard Algae?

    According to this post from a previous topic you aren't shocking your pool enough. If you read the initial post there is a chart that tells you shock levels to use for mustard algae.
    If your CYA is 30-40 you should be shocking your pool to 24 according to the chart done by Chemgeek to get rid of the mustard algea
    Les
    Don't have a pool right now. Just sharing what I have learned over the years!
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    Re: Mustard Algae?

    can you shock up to 25?
    Brian
    20K IG Gunite w/ raised 7ft spillover spa. 1.5 HP Hayward Northstar pump 425 sq ft Hayward cartridge filter, Colorlogic lights AquaRite SWG AquaLogic PS-8 control
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    Re: Mustard Algae?

    OK, I am going to take it up to 25. I did shock it to those levels this spring when we opened, but the levels never held overnight then either. I just gave up the fight and let the kids swim.
    I'm wondering thought if it's still OK to swim at that level. My 4 year old may go through withdrawals if he can't get in the pool for a few days.
    28' AG, 17000 gal., sand filter

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    Re: Mustard Algae?

    that's a little too high to be swimming in. I think under 10 is OK.
    Brian
    20K IG Gunite w/ raised 7ft spillover spa. 1.5 HP Hayward Northstar pump 425 sq ft Hayward cartridge filter, Colorlogic lights AquaRite SWG AquaLogic PS-8 control
    1hp pump for sheer descent

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    frustratedpoolmom's Avatar
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    Re: Mustard Algae?

    I think the mustard/yellow shock level is a 24 hour shocking target, not for long term shocking....thought I read that on here somewhere????
    Helpful links: Pool School; CYA/Chlorine Chart
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    TizMe's Avatar
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    Re: Mustard Algae?

    Im not sure about the time factor perhaps someone who knows better can chime in
    Les
    Don't have a pool right now. Just sharing what I have learned over the years!
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    frustratedpoolmom's Avatar
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    Re: Mustard Algae?

    I'm still looking for the comment I thought I saw, but so far I appear wrong, here's some advice I did find....

    I found this from last year, by Chem Geek

    "For yellow/mustard algae, you need to shock with 60% of your CYA level so 15-18 ppm FC, in your case with 25-30 ppm CYA. Lower your pool's pH to 7.2 before shocking and then maintain the shock level for at least 2 days (3 is better). Yes, put the ladder and anything else that will going back into the pool which includes poles, brushes, etc. Wash your swimsuits with hot soapy water (yes, they may fade slightly, but it's ensure you won't reintroduce the algae). If you use a pool cover, have it on the pool during one day and night during this process.

    To ensure keeping away this algae, you will need to maintain a minimum FC level of 15% of the CYA level (about the "Max" column in Ben's Best Guess Chart).

    for CYA of 40 that's about 6ppm, that's your MINIMUM free chlorine level...

    JMHO, Your description of brown / yellow dust in the divits doesn't sound like yellow algae to me, but the significant chlorine drop overnight is perplexing.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
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    Re: Mustard Algae?

    I digress....the "description" sounds like Mustard....but....look at this site I found via google. It has pics! Does this resemble your situation?

    The reason I ask is I get the dirt/dust in the divets but I experience very little FC drop, .5 to 1ppm per day, full sun.

    These pics are facsinating. I'm gonna keep looking.

    Oh I did see another post that said mustard shock requires REALLY HIGH levels of chlorine, for several days....so if that is your situation you definetly aren't shocking enough or high enough.

    We'll get this figured out!
    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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    Re: Mustard Algae?

    Last one and I'm headed out - G.N.O!

    Found this on Google...Richard gets around...

    chem geekJun 16 2008, 08:13 PM
    "It sounds like sand or dirt to me. Most algae has a slimier feel to it. Mustard/yellow algae tends to like the shady side of the pool. If you can carefully scoop some up, then you can try a bucket test to see if it grows. You can also look at it under a microscope. Dirt is very solid and irregular; pollen is usually round and sometimes spiky but somewhat solid in appearance; algae is usually more translucent (you can see organelles inside) and often oblong or rectangular."

    Got a microscope?
    Seriously, does it feel slimy? Is it in the shade?

    Try the scooping method and see if it grows in a bucket. That seems easiest if you don't have a microscope!
    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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    Re: Mustard Algae?

    Of coarse on a day I really would like to use the computer, a huge storm had to come through and knock the power out for a few hours...
    I just went and checked the pool and FC is down to 11.5ppm. Granted it rained to beat heck here for a while, but that seems like a huge drop in FC. I added 3 big jugs of bleach and that should get me up to 27ppm. I will check before I go to bed tonight.
    As for where the algae is located, it's all over the pool, not just on the shady side. I pulled the solar cover back to see if I could try to get a picture, but of coarse now the whole pool is dirty from the rain. I couldn't tell the algae from the dirt. I can honestly say that last year it was confined to the shady side of the pool, but not anymore. I could definitely see improvement today (before the rain), there was hardly any to vacuum up. Before I started shocking all the divets we have on the bottom of the pool and the wrinkles in the liner would be filled every day. I can't say if it particularly slimy or not, but it does kind of "poof" if you try to touch it. I thought it may be pollen so I bought a skimmer sock but so far I have not found it to be filled with anything other than bugs and tree buds.
    I read that post from chem geek last year. I tried the bucket test and it was inconclusive. I don't know if I ever got any of the algae in the dropper I was using because as I said it kind of poofs when you touch it. Between that and 2 kids and a dog up on the deck playing with it (I wanted it in the same sun the pool was getting), I couldn't tell if anything grew or not.
    frustratedpoolmom, I could not see a link to any pictures you found. And no, I don't have a microscope
    28' AG, 17000 gal., sand filter

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    Re: Mustard Algae?

    One more thing I forgot to mention. I am planning on shocking tonight, tomorrow and tomorrow night but I am going out of town for 5 days on Sat. morning. Will this be long enough to kill the pesky stuff?
    28' AG, 17000 gal., sand filter

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    TizMe's Avatar
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    Re: Mustard Algae?

    I read a post earlier today where someone shocked their pool put the cover on and went away for a few days and when they got back the chlorine levels were just coming back to normal levels with no algae, so it worked for them. You however already have an algae bloom you suspect so shocking it will likely prevent more from growing but since its already established in the pool it wont keep it away IMO.You need to as much as you can brush the pool and vacuum and clean the filter before you go away.

    Have a good time !
    Les
    Don't have a pool right now. Just sharing what I have learned over the years!
    Helpful Links:
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    Re: Mustard Algae?

    Something doesn't quite fit here. A couple of days at regular shock level should cause mustard algae to appear to go away or nearly all go away, only to have it return as soon as the FC level comes down again.

    Very fine blown in dust and/or pollen sometimes gets mistaken for mustard algae. Mustard algae usually grows on the shady side of the pool and tends to look something like:


    Dust tends to settle in places where the circulation slows down and in uneven patches of floor. Dust/pollen will not be affected by shocking, it will be just as common at high FC levels as at low FC levels.

    But then you have a significant loss of FC overnight. Which does tend to argue for mustard algae, or something more than just dust/pollen.

    So I have a couple of questions.

    How sure are you of the CYA level? High CYA levels and regular algae could cause the behavior you describe.

    Have you checked for FC loss overnight on other nights? Is it always that dramatic?

    If you let the FC come down below 10, is the PH still reasonable? Does the "mustard algae" increase?

    Have you brushed absolutely everywhere while the FC level was high, preferably once a day?

    Do you have anywhere where the circulation is particularly bad, behind steps, light niches, etc? Have you looked there to see if there is algae hiding there?
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    frustratedpoolmom's Avatar
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    Re: Mustard Algae?

    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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    Re: Mustard Algae?

    Good Morning!
    I checked the water last night, and I did shock it to 27. This morning it was down to 25. So something is still in there. I brought the level back up to 30 this morning with my last 2 jugs of bleach, off to the store to get more. I will also pull back the solar cover at noon to see what it looks like.
    As far as your other questions, here goes:
    - I checked the CYA level again this morning and it is leaning more towards the 30. We have had 2 huge storms here in the last day and I had to drain lots of water from the pool. So yes, I'm fairly confident on that number.
    - I haven't checked the PH since I started shocking, I thought it would be skewed because of the high FC.
    - I have been vacuuming as much of the bottom of the pool as I can everyday, and also using the brush on the walls. I'm sure I'm not getting 100%, but I'm trying my best. We don't have any lights or anything and I'm brushing and vacuuming under the ladder (which doesn't touch the bottom of the pool). I don't know about bad circulation, we have a pretty good whirlpool effect from the way my DH pointed the return eye this spring. My 2 year old floats in a circle pretty fast in her floatie!

    Looking at the pictures you posted, it doesn't look like my stuff. But I have looked and looked at this for the last year trying to figure out what it is and some pics I see look like what I have. I keep the pool covered all day with the solar cover except for when we are in it, trying to preserve what little heat we have. Once in a while I will go out in the late morning to take it off if it's going to be a sunny day and we won't go in until afternoon. So I would think that if it was dust it would stay mostly on the cover, no?

    Anyways, I'm shocking high tonight and tomorrow morning. I will put the cover on with a floater and some tabs tomorrow morning since I have some room to go up on the CYA. We will see what I come home to on Wed!

    PS frustrated, I'm a former Chicago south sider, grew up in Tinley Park!
    28' AG, 17000 gal., sand filter

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    Re: Mustard Algae?

    Quote Originally Posted by MNpoolmom
    Good Morning!
    I checked the water last night, and I did shock it to 27. This morning it was down to 25. So something is still in there. I brought the level back up to 30 this morning with my last 2 jugs of bleach, off to the store to get more. I will also pull back the solar cover at noon to see what it looks like.
    As far as your other questions, here goes:
    - I checked the CYA level again this morning and it is leaning more towards the 30. We have had 2 huge storms here in the last day and I had to drain lots of water from the pool. So yes, I'm fairly confident on that number.
    - I haven't checked the PH since I started shocking, I thought it would be skewed because of the high FC.
    - I have been vacuuming as much of the bottom of the pool as I can everyday, and also using the brush on the walls. I'm sure I'm not getting 100%, but I'm trying my best. We don't have any lights or anything and I'm brushing and vacuuming under the ladder (which doesn't touch the bottom of the pool). I don't know about bad circulation, we have a pretty good whirlpool effect from the way my DH pointed the return eye this spring. My 2 year old floats in a circle pretty fast in her floatie!

    Looking at the pictures you posted, it doesn't look like my stuff. But I have looked and looked at this for the last year trying to figure out what it is and some pics I see look like what I have. I keep the pool covered all day with the solar cover except for when we are in it, trying to preserve what little heat we have. Once in a while I will go out in the late morning to take it off if it's going to be a sunny day and we won't go in until afternoon. So I would think that if it was dust it would stay mostly on the cover, no?

    Anyways, I'm shocking high tonight and tomorrow morning. I will put the cover on with a floater and some tabs tomorrow morning since I have some room to go up on the CYA. We will see what I come home to on Wed!

    PS frustrated, I'm a former Chicago south sider, grew up in Tinley Park!
    I'm right by Tinley Park! (For those who don't know, Homer Glen is a new suburb, formed out of an unincorporated area between Orland and Lockport in 2001.) Next question, sox fan or cub fan?

    Is your 'stuff' growing on the walls? Or do you only see it in the floor divets?

    I too leave my cover on when not in use, and I still get the dusties. So I don't think it prevents that much. Especially in areas that are subject to windy conditions, like me!

    You may have the same issue with the dusty stuff when you return home but at least your pool won't be pea soup green! Enjoy your vacation!
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
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    Re: Mustard Algae?

    Well, I grew up on the south side so it was definitely the Sox. But since moving to MN when I got married 12 years ago, I tend to lean more towards the Twins
    No, I guess now that I think about it we never have any algae on the walls.
    I shocked the pool again last night to 30 and will bring it back there this morning. We leave in a few hours so we will see what it's like when we get back. I'm keeping my fingers crossed!
    Thanks for you help!
    28' AG, 17000 gal., sand filter

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    Re: Mustard Algae?

    I hope you have a wonderful trip!
    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: Mustard Algae?

    Thanks everyone! The trip was great and I returned home to a sparkling clean pool, except for what I have come to realize is dirt at the bottom of the pool. But the FC was at about 8, after having a friend dump some bleach in for me on Monday night.
    I'm wondering now if we don't have a problem with the filter. I found a little bit of sand in my skimmer sock last week. We did have a problem last year with a broken lateral, but haven't had any problems since then. What are symptoms of a problematic filter?
    28' AG, 17000 gal., sand filter

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