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Thread: Is this black algae?

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    Is this black algae?

    I'm worried I have black algae. I've ordered a stainless brush and ready to attack....Is it? Any direction on what to do if it is? I have scrubbed and have good FC, and this stuff is still around...



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    Patrick_B's Avatar
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    Re: Is this black algae?

    It's hard to say from these shots, and something has been lying there or disturbed it in some way, which is kind of strange for BA. You say the Chlorine is good, so can you post a full set of test results please?
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    Re: Is this black algae?

    Some of these are a little old, but don't fluctuate much for me. Results from poollogger.com

    FC: 7
    CC: 0
    PH: 7.8
    TA: 150
    CH: 450
    CYA: 50
    Temp: 68


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    Hayward DE 4280 Filter
    Pentair Superflo SS Pump
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    Old Broken Heater that needs to get replaced!

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    Patrick_B's Avatar
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    Re: Is this black algae?

    Ok, how old are they, and can you run a fresh set tomorrow? If your FC and Cya never deviated from this...and from a time the pool was completely Algae free, you won't have black Algae. But we know that isn't the case, especially if that is some type of Algae. When you say the Chlorine is good, and post old results we don't have anything to work with.

    Is it anywhere else in the pool? Somewhere you can touch it, and pinch some of maybe, or smudge it? If so, tell us what happens. What happens when you brush it with a normal brush? Black Algae grows when there is a lack of ample Chlorine often, and or for extended periods. Based on what you say, it shouldn't be, but more info is needed for us to help determine that.

    Lastly, if you've had BA in the past, it is extremely likely you never got the roots and killed it all. This happnes a lot, so has that ever been the case?
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    Re: Is this black algae?

    Quote Originally Posted by Patrick_B View Post
    Ok, how old are they, and can you run a fresh set tomorrow? If your FC and Cya never deviated from this...and from a time the pool was completely Algae free, you won't have black Algae. But we know that isn't the case, especially if that is some type of Algae. When you say the Chlorine is good, and post old results we don't have anything to work with.

    Is it anywhere else in the pool? Somewhere you can touch it, and pinch some of maybe, or smudge it? If so, tell us what happens. What happens when you brush it with a normal brush? Black Algae grows when there is a lack of ample Chlorine often, and or for extended periods. Based on what you say, it shouldn't be, but more info is needed for us to help determine that.

    Lastly, if you've had BA in the past, it is extremely likely you never got the roots and killed it all. This happnes a lot, so has that ever been the case?
    Most the results are about a week old. I am guilty of letting FC drop at times. I travel and super busy. I have some of this in the past, like a year ago, but this came back recently in the same area but is already spreading further on the bottom. I can do more recent results but they will be similar.

    What's the best way to get some and smear it?


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    Re: Is this black algae?

    Quote Originally Posted by Uavmx View Post
    Most the results are about a week old. I am guilty of letting FC drop at times. I travel and super busy. I have some of this in the past, like a year ago, but this came back recently in the same area but is already spreading further on the bottom. I can do more recent results but they will be similar.

    What's the best way to get some and smear it?


    Sent from my iPhone using Tapatalk
    When I brush with a normal brush I don't see much. I little bit of a cloud as in push along


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    Re: Is this black algae?

    If you've had it in the past, it's likely you never killed it all, and or the roots. It's difficult to do actually, and coupled with low FC it would be no surprise to see it again. BA grows roots down into plaster, and a good SLAM with prolonged higher FC targets without drops below minimum are your only chance. This includes brushing, usually with the SS brush as well. This is really not unheard of in old pools where it has taken hold, as it is a very tough Algae to defeat. If you can get to some, it will smudge some sort of Green-Greenish color while appearing nearly black sitting undisturbed.
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    Re: Is this black algae?

    Quote Originally Posted by Patrick_B View Post
    If you've had it in the past, it's likely you never killed it all, and or the roots. It's difficult to do actually, and coupled with low FC it would be no surprise to see it again. BA grows roots down into plaster, and a good SLAM with prolonged higher FC targets without drops below minimum are your only chance. This includes brushing, usually with the SS brush as well. This is really not unheard of in old pools where it has taken hold, as it is a very tough Algae to defeat. If you can get to some, it will smudge some sort of Green-Greenish color while appearing nearly black sitting undisturbed.
    Here's latest numbers, I had to add water to the pool over the weekend and I also ran out of bleach, so no surprise my Fc is low. I just added more bleach and water trying to get above 10fc. Will retest soon. I ran out of agent to test cya as well....lol horrible me.

    I bought a stainless steel brush and began brushing. It's not removing it so at this point is it safe to say it's black algae?
    What should me target Fc be?
    Do I run the pump non stop?
    Should I back flow it?
    How do I know when I've gotten rid of the algae?
    Results from poollogger.com

    FC: .5
    CC: .5
    PH: 7.7
    TA: 150
    CH: 450
    CYA: 50
    Temp: 72



    ~14k Gallon IG Plaster (old)
    Hayward DE 4280 Filter
    Pentair Superflo SS Pump
    Built 1993
    Old Broken Heater that needs to get replaced!

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    Is this black algae?

    Quote Originally Posted by Uavmx View Post
    Here's latest numbers, I had to add water to the pool over the weekend and I also ran out of bleach, so no surprise my Fc is low. I just added more bleach and water trying to get above 10fc. Will retest soon. I ran out of agent to test cya as well....lol horrible me.

    I bought a stainless steel brush and began brushing. It's not removing it so at this point is it safe to say it's black algae?
    What should me target Fc be?
    Do I run the pump non stop?
    Should I back flow it?
    How do I know when I've gotten rid of the algae?
    Results from poollogger.com

    FC: .5
    CC: .5
    PH: 7.7
    TA: 150
    CH: 450
    CYA: 50
    Temp: 72



    Sent from my iPhone using Tapatalk
    Latest after retest. I put more bleach in to get up towards 18fc.

    Results from poollogger.com

    FC: 10.5
    CC: .5
    PH: 7.7
    TA: 150
    CH: 450
    CYA: 50
    Temp: 72

    ~14k Gallon IG Plaster (old)
    Hayward DE 4280 Filter
    Pentair Superflo SS Pump
    Built 1993
    Old Broken Heater that needs to get replaced!

  10. Back To Top    #10

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    Re: Is this black algae?

    Retested and scrubbed today, I lost nearly 10FC over night, is that possible? Results from poollogger.com

    FC: 7
    CC: 1
    PH: 7.8
    TA: 150
    CH: 450
    CYA: 50
    Temp: 72


    ~14k Gallon IG Plaster (old)
    Hayward DE 4280 Filter
    Pentair Superflo SS Pump
    Built 1993
    Old Broken Heater that needs to get replaced!

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    Patrick_B's Avatar
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    Re: Is this black algae?

    Oh yes, it's very possible. Two things eat Chlorine, Sunlight, and Organics. This can be Algae or anything living, or that once was. Sweat, Urine, all those things and a few more put a demand on Chlorine and consume it.

    Follow the SLAM procedures to the letter from here and don't stop. This is how you kill all Algae, but you have to destroy all the organics with Chlorine, and you have some no doubt. Once you get ahead of those, there will be less, and less demand on the Chlorine but it may take a lot for a little while. If you can reduce the Cya to 30 by replacing some water, it will take a little less added to the pool for the same effect.
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    Re: Is this black algae?

    Could my pH being high cause this colorization? I've hard time testing pH because it's been dark, tested today and I think I'm over 8....I had to add 4 drops of r005 to get it to look like 7.8. what do I do? FC was back down again in one night 10 or so.

    Numbers before adding bleach

    Results from poollogger.com

    FC: 8
    CC: 0
    PH: 8
    TA: 150
    CH: 450
    CYA: 50
    Temp: 72


    ~14k Gallon IG Plaster (old)
    Hayward DE 4280 Filter
    Pentair Superflo SS Pump
    Built 1993
    Old Broken Heater that needs to get replaced!

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