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Thread: Black Algae again

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    Black Algae again

    I have been fighting black algae for 10 days now. Let my FC slip at times so almost starting over again. I have also been running my SWG for 24/7 for the past 10 days as well so fighting the PH levels cause they keep rising. The pool calculator does not indicate the shock level for black algae so not sure what to use. Sort of been in between. I do have progress but daily brushing and tons of bleach the black algae still there, although slightly improved. Here are my readings as of today.

    FC 14
    PH 7.8
    CH 400
    TA 70
    CYA 30
    Salt 3100

    Should I keep the SWG running 24/7 until black algae at bay? Any help would be appreciated.
    20'x 40'--27,000 Gal--Plaster Pool
    Sand Filter, IG, Aqua Rite SWG

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    Re: Black Algae again

    Got a pic?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    y_not's Avatar
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    Re: Black Algae again

    No need to test pH, the test is quite inaccurate above 10ppm FC and much above that it's not even worth it. So simply don't bother at high chlorine levels.

    Also, how far did your FC drop? Since you're at 14, you have a bit of room as your shock level is 12ppm. These really aren't hard and fast numbers, just guidelines. So if it's an issue, bump it up a bit as a buffer when you go to bed, or have to leave, or for daytime.

    As for pH, it will naturally rise anyway when shocking as a result of the large amounts of CL addition. This is perfectly normal and all part of the chemistry, just ignore it till you're done shocking.

    I don't own an SWG, but I understand them quite well. I wouldn't run it all the time, IE. regular schedule. But I would use it to help keep my FC levels up during the daytime when the sun eats/consumes CL, or when you're gone and can't add, only if that means the difference between your FC levels dropping below shock and not. Otherwise I'd just leave it off, what with the high pH which can cause troubles for the cell. Running it a bit here and there to boost things probably isn't going to be an issue though.

    If you do leave it on, you'll already have a bit of a feel for how much you're loosing as you shock, in turn, you'll know how to set your SWG run-time appropriately. You are running your pump 24/7 while shocking and keeping an eye on your filter pressure, right?

    Lastly, with an SWG cell, your CYA is waaaayyyyyyyy too low. Ignore what the manuf. says, they're wrong, CYA needs to be 70-80ppm. Your other levels all look fine, high CH, but sometimes you can't help that. That's where your TA & pH come in to keep the scaling in check. Chemistry is your friend, use it.
    Thanks for reading... - Tony
    Da' Pool: Intex 15'x42" 3284gal AGP EasySet (Inflatable Ring) - (Summer 2014: 27' round EW /w 6.5' deep end @ 22,500gal)
    Pump & Cart Mod: 1000gph Cart. 5ft² - 2 nylons, 24/7 OP. Traps bugs/bits, lasts longer/cleans easier = Happier Pool Owner!!
    The Bible for a "Trouble Free Pool" life = PoolSchool, the BBB method a TF100 test kit(Recommend Kits Compared). - Cleaning a Sand Filter
    Water looks like GLASS, if yours doesn't...SLAM IT! Feels nice and never been happier!!! :D

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    Re: Black Algae again

    Don't add CYA until you resolve your issues with algae. A pic usually helps to identify black algae.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Black Algae again

    thanks for the help. I thought my shock level for black algae was the same as mustard so I bumped my FC to 18 which is what it is this morning from last night.
    thought my PH was high so dropped in small amount of acid and PH now at 7.5.
    I know my CYA is to low but waiting until finished shocking to raise...thought that was the procedure since it takes less bleach to shock.
    Been trying to add pic but not sure how and it wont let me.
    It tested with scratch and it slimy and also with vitamin c to make sure it not iron and it would not come off so assumed black algae.

    numbers for this morning is
    PH 7.5
    FC 18
    CH 400
    TA 70
    CYA 30

    So, should I keep running SWG 24/7 with out it generating chlorine or put it back on at say 70% and run 12 hours day like normal.
    Black algae not getting worse but slow to come off.
    Oh and i am brushing twice a day.
    Thanks for all the help.
    20'x 40'--27,000 Gal--Plaster Pool
    Sand Filter, IG, Aqua Rite SWG

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    Re: Black Algae again

    You can use mustard algae shock level if you want. It should make completing the shock process happen a little faster.

    For the pics, lots of us use PhotoBucket.com. It's free. Upload the pics & then just copy the IMG code and paste it the post and the image will appear when you hit preview or submit.

    Are you brushing with an algae brush? Wire/SS brush?

    ETA: I'd turn off the SWG until you are done shocking.
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    Re: Black Algae again

    Thanks will try adding pics.
    I am brushing with wire brush.
    20'x 40'--27,000 Gal--Plaster Pool
    Sand Filter, IG, Aqua Rite SWG

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    Swampwoman's Avatar
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    Re: Black Algae again

    Do you live near an ocean? Black algae is kind of rare depending on where you're from.

    Re pic, maybe if you resize it you can load it. Eg. I can't load them from iPad, but desktop works fine. Just use the "full editor" then at bottom of post area trigger the attachment feature, then put it inline.
    In ground extended Grecian, 22,000 gal, Hayward 220t sand filter, vinyl liner, dolphin m4 supreme.
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    Re: Black Algae again

    I live 30 miles from gulf of mexico in Louisiana. I think it more of a neglect issue by me than mother nature. hope the pic is attached.
    [img]IMG_0654[/img]
    20'x 40'--27,000 Gal--Plaster Pool
    Sand Filter, IG, Aqua Rite SWG

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    Re: Black Algae again

    trying to add pic again.
    Attached Images Attached Images
    20'x 40'--27,000 Gal--Plaster Pool
    Sand Filter, IG, Aqua Rite SWG

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    Re: Black Algae again

    Pic is a bit small but viewable. That pic and your added explanations make me think it is black algae, too.

    You must keep your chlorine levels at shock value until it's gone....standard shock values are fine.

    The important part of black algae is they must be brushed daily with a stainless steel brusk to knock of the biofilm that forms on the surface making black algae very chlorine resistant. Twice a day is even better if you can muster the time.

    The stainless brush is a requirement to really "scrape" the top surface of thew algae so it can be killed.

    Perseverance will win that WAR.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Black Algae again

    Trying to brush 3 times a day right now.
    Its working but tiring.
    Should I run SWG 24/7 until its all gone??
    Currently I have the setting to 0 while I ma shocking.
    Thank for all your help.
    20'x 40'--27,000 Gal--Plaster Pool
    Sand Filter, IG, Aqua Rite SWG

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    y_not's Avatar
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    Re: Black Algae again

    Quote Originally Posted by duraleigh
    Don't add CYA until you resolve your issues with algae. A pic usually helps to identify black algae.
    Sorry about that duraleigh, I forgot to tell the OP to wait till the algae problem is resolved before adding CYA. I was just simply giving advice on the the numbers in general. My baaaadddd!
    Thanks for reading... - Tony
    Da' Pool: Intex 15'x42" 3284gal AGP EasySet (Inflatable Ring) - (Summer 2014: 27' round EW /w 6.5' deep end @ 22,500gal)
    Pump & Cart Mod: 1000gph Cart. 5ft² - 2 nylons, 24/7 OP. Traps bugs/bits, lasts longer/cleans easier = Happier Pool Owner!!
    The Bible for a "Trouble Free Pool" life = PoolSchool, the BBB method a TF100 test kit(Recommend Kits Compared). - Cleaning a Sand Filter
    Water looks like GLASS, if yours doesn't...SLAM IT! Feels nice and never been happier!!! :D

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    Re: Black Algae again

    Trying to brush 3 times a day right now. Its working but tiring.
    Yeah, I get it on the "tiring" part. I am not sure 3 times daily is mandatory. Of course, it never hurts to brush as much as you want but a morning and night "scraping" might be almost as effective.

    Running the SWG is up to you. Generally, we like to think of SWG's as maintainers of normal chlorine levels but not really designed to keep the high FC levels your situation requires.

    If it were my pool, I think I would simply leave it at it's daily setting to "assist" but use good ole' bleach to boost your FC levels up to maintain shock value. This process will take you a while. Keep at it until you see NO visible signs of the algae.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Black Algae again

    Thanks Dave...will keep at it...might look like Arnold Swartz...when I'm done.
    LOL
    20'x 40'--27,000 Gal--Plaster Pool
    Sand Filter, IG, Aqua Rite SWG

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