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Thread: Black Algae

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    Black Algae

    I think I am dealing with black algae. It is stuck to the bottom of my pool. I have gotten a little lazy with testing my water and have just been adding some bleach when the the water wasn't sparkling as much as I thought it should be!!!

    I have tested my water today and here are my results:

    FC - 0
    CC - 0
    pH - 7.8
    TA - 140
    CH - 160
    CYA - 25 (It was down to about 10-20 and I added a little bit of stabilizer to get it back up to at least 30)

    Some of the black spots are REALLY stuck. I am brushing the bottom with a broom and still cannot get some of them loose. Is the answer still to shock and that is all??? Will that kill the algae and then I will be able to get it loose???? I cannot believe that my pool is NOT green!! It is not crystal clear today but it is no where near cloudy. The Pool Calculator told me the shock level is 12 so I will be adding 3 jugs of bleach. (182 oz jugs)

    Our motor was really LOUD (it was going bad) so we had to replace it. Second problem: this new motor is a Waterway Eco-Kleer 1.5 hp. Ever since we got it the vacuum cleaner is just not doing the job it did with the old Hayward!!! You would think it would be doing a LOT better but barely moves around and won't hardly vacuum anything!! I have tried adjusting the cleaner but to no avail. This cleaner was purchased last year! It is a Kontiki Barracuda.

    Any suggestions??? I run my filter 24/7. It is a sand filter but now has Zeolite will need to be changed next year.

    I also need to get a new cover. We have LOTS of trees so therefore we have LOTS of leaves!!! Our last cover was mesh but it only lasted 2 years! Is that average????
    Any suggestions????
    20ft round; sand; AG; vinyl

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    Mod Squad zea3's Avatar
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    Re: Black Algae

    Bring your FC back up to 6 and see how much the FC drops during the day. If your FC drops rapidly then you may need to go through the shock process.

    If you have any chlorine pucks around, try rubbing one on one of the spots and see if it lessens it.

    Your old pump motor may have been rated higher than your new pump. Was the old motor also a 1.5 hp?
    TFP Moderator
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    Vogue 21' round AG, Pentair 1 hp 2 speed pump, 36 sq ft DE filter, Hayward S180T 150# sand filter, Houston, Texas
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    Re: Black Algae

    yes. it was a 1.5, too.
    do not have any chlorine pucks since all i use is bleach.
    i shocked it to 12 last night but have not been out this morning to get a reading.

    *******************


    have tested my water today and here are my results:

    FC - 3
    CC - < .5
    pH - 8.0
    CYA - 10 (must have read it wrong yesterday because I filled the tube all the way to the top now before the dot disappeared!!) But have already added stabilizer and will give that time to register.

    Pool Calculator says to shock it to 10. will go do that now.
    Am I on the right track????
    Any other suggestions to get the algae off the bottom????

    My fill water usuallly runs about 7.6-7.8. It is REALLY hard to keep it in the lower levels. What is the highest I can keep it without causing problems. I am out of M/A and will try to get some today.
    20ft round; sand; AG; vinyl

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    Mod Squad zea3's Avatar
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    Re: Black Algae

    As far as the pump goes, some pumps are fully rated and some are not. That will also affect how the pump performs. I do not know much about pump ratings beyond that, but I'm sure one of the mechanically inclined people will be along to explain how that works.

    HTH sells individually packed pucks. Sometimes you can find them at Walmart, Target, Home Depot, or other places that sell that brand. If you know someone who uses pucks maybe you can borrow one from them.

    When you post a current FC let us know what time you added the bleach so we can tell if the drop is from sun exposure or possible organics in the water.
    TFP Moderator
    Helpful links: TF Test Kits,TFP Pool School, PoolMath
    Vogue 21' round AG, Pentair 1 hp 2 speed pump, 36 sq ft DE filter, Hayward S180T 150# sand filter, Houston, Texas
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    Re: Black Algae

    I added the bleach last night probably around 8:00 pm.

    What about pH levels??? What is the highest I can get by with???
    20ft round; sand; AG; vinyl

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