Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 10 of 10

Thread: Black algae question

  1. Back To Top    #1

    Black algae question

    Based on pictures and what I've read here and on other sites, I am sure that I have black algae.

    I just had my water tested with these results:

    TDS: 4000
    CYA: 53
    Total Chlorine: 2.8
    Free Chlorine: 2.7
    pH: 8.2
    Total Alkalinity: 94
    Total Hardness: 238
    Minerals: 2800


    I purchased a Taylor test kit while I was there.

    What is my next step?
    Baltimore, Maryland
    28,000 gallons
    Filter C&C 420
    Sanitizer Mineral Springs
    Plaster in Ground

  2. Back To Top    #2

    In the Industry
    X-PertPool's Avatar
    Join Date
    Jun 2009
    Location
    Exeter, PA
    Posts
    1,385

    Re: Black algae question

    Black Treat from United Chemical works,there are also other methods too. but you will still need to keep your FC at atleast 3ppm (or higher) to keep it away. You will need a good brush to dislodge the black algae from the surface, it will usually leave a ring after it's brushed off.
    -Kevin
    X-Pert Pool Service
    x-pertpool.com
    X-Pert Pool on Facebook and @XPertPoolServic on Twitter
    22,000 gal / 16' x 32' / Vinyl / Hayward s244t /Pentair SuperFlo 1 hp

  3. Back To Top    #3

    Re: Black algae question

    I purchased a SS brush head. How should I raise the FC?
    Baltimore, Maryland
    28,000 gallons
    Filter C&C 420
    Sanitizer Mineral Springs
    Plaster in Ground

  4. Back To Top    #4
    Mod Squad zea3's Avatar
    Join Date
    Jul 2009
    Location
    Houston, Texas
    Posts
    7,569

    Re: Black algae question

    Plug your test numbers intothe Pool Calculator. You will need to bring the chlorine up to shock levels and hold it there until you pass the overnight FC test. You also need to bring your PH down, and brush the pool well during the shocking process.

    EDIT: Also read through Pool School and the instructions for defeating Algae.
    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
    Love TFP? Become a
    TFP Supporter!

  5. Back To Top    #5
    reebok's Avatar
    Join Date
    Apr 2009
    Location
    Lakeland, FL
    Posts
    1,268

    Re: Black algae question

    I would return the taylor test kit and get my money back unless it's a k-2006 with a FAS-DPD (not DPD) chlorine test and order one from http://www.tftestkits.net which is a better value.
    your FC level is too low for your CYA level. see the chart here: pool-school/chlorine_cya_chart_shock
    your ph is also too high. I would lower the ph then start shocking. since you have black algae, you may have other organics, and high fc levels will help kill the black algae.
    pool-school/shocking_your_pool

    I personally believe based on my one single personal experience that the best way to get rid of black algae spots is to rub a trichlor puck on them for however long it takes (days probably) to kill it. of course if you have hundreds of spots, it's different, but you didn't say so I don't know.

    the chlorine you should be using is bleach or liquid chlorine if your pool store has it and it's a better deal. keep in mind that liquid chlorine will be roughly twice as strong as bleach, so keep that in mind with the price.
    16x32 21,000 gallon in-ground exposed aggregate, 1.5hp pump, 120 sqft catridge filter, birdcage, solar panels, aquavac tigershark qc robot.

  6. Back To Top    #6

    Re: Black algae question

    I put my numbers into the calculator and it said to replace 100% of my water.....Please tell me there is another option, or that I did something wrong!
    Baltimore, Maryland
    28,000 gallons
    Filter C&C 420
    Sanitizer Mineral Springs
    Plaster in Ground

  7. Back To Top    #7
    reebok's Avatar
    Join Date
    Apr 2009
    Location
    Lakeland, FL
    Posts
    1,268

    Re: Black algae question

    16x32 21,000 gallon in-ground exposed aggregate, 1.5hp pump, 120 sqft catridge filter, birdcage, solar panels, aquavac tigershark qc robot.

  8. Back To Top    #8
    Guest

    Re: Black algae question

    Quote Originally Posted by Dreimer
    Based on pictures and what I've read here and on other sites, I am sure that I have black algae.

    I just had my water tested with these results:

    TDS: 4000
    CYA: 53
    Total Chlorine: 2.8
    Free Chlorine: 2.7
    pH: 8.2
    Total Alkalinity: 94
    Total Hardness: 238
    Minerals: 2800


    I purchased a Taylor test kit while I was there.

    What is my next step?
    Which taylor kit? If you got a K-2006 you are fine. If you got a K-2005 you need to get a stand along FAS-DPD test kit from either Taylor or TFTestkits. If you got any other kit from Taylor return it and get a K-2006 or the TFtestkit TF-100. Also, pick up some AquaChek salt test strips and some LaMotte Borate test strips.
    Bring your salt up to 3200-3400 ppm, get your CYA up to 80 ppm, AND GET YOUR pH in line! Ignore TDS it is not valid when you have a salt system!!!!!!!!
    Stop wasting your money on beginnings and renewal and test and adjust your salt, borates, and CYA separately! (These expensive products are just salt, borax, and CYA!) It will save you a lot of money, give you better control of your water, and prevent problems like your current one!

    Black algae only appears when a pool has bee operated with too low a chlorine level for a period of time. it is slow to appear and take hold. I suspect that because of your high pH and prpbably scling to your cell that you have gone throuhg periods of no chlorine production.
    How many hours a day do you run your pump and what is your cell output?
    Here is something you might find useful:
    water-balance-tips-for-a-swg-t3663.html

  9. Back To Top    #9
    frustratedpoolmom's Avatar
    Join Date
    May 2007
    Location
    SWSuburban Chicago, IL
    Posts
    11,963

    Re: Black algae question

    Quote Originally Posted by reebok
    I would return the taylor test kit and get my money back unless it's a k-2006 with a FAS-DPD (not DPD) chlorine test and order one from http://www.tftestkits.net which is a better value.
    your FC level is too low for your CYA level. see the chart here: pool-school/chlorine_cya_chart_shock
    your ph is also too high. I would lower the ph then start shocking. since you have black algae, you may have other organics, and high fc levels will help kill the black algae.
    pool-school/shocking_your_pool

    I personally believe based on my one single personal experience that the best way to get rid of black algae spots is to rub a trichlor puck on them for however long it takes (days probably) to kill it. of course if you have hundreds of spots, it's different, but you didn't say so I don't know.

    the chlorine you should be using is bleach or liquid chlorine if your pool store has it and it's a better deal. keep in mind that liquid chlorine will be roughly twice as strong as bleach, so keep that in mind with the price.
    What he said.

    If you follow the instructions for shocking the pool, and keep the FC elevated slightly above the "normal" levels on the CYA chart, brushing daily, several times a day, the brushing/chlorine combo will kill the black algae and maintaining proper FC levels for the future will make any residual stains fade and prevent any repeat. Like RB said, if there are few spots, a trichlor puck will work too.

    I would not recommend any pool store chem called "Black Treat" or anything else of that nature.

    I also recommend you get the K-2006 or the TF100 test kit. Accept no substitutes!

    Hope this helps.
    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

  10. Back To Top    #10
    Guest

    Re: Black algae question

    Get yoru water balanced and your SWG operating properly like I suggested and after you have done so start shocking. I would also check the SWG for scale deposits. Black algae is very slow growing so you have time. You want to correct the conditions that caused it to grow in the first place. My guess is your water balance has been off for your SWG for quite some time now. Your very high pH and too low a CYA are both red flags!
    To kill the black algae it will take a lot of brushing and high chlorine. Once you get everything in line bring your FC up to about 35 ppm and keep it there. Brush the spots several times a day. The more you brush the faster you will kill it all. NO SWIMMING WITH THE CHORINE THIS HIGH! It can take a week or longer to kill the algae but it took a month or longer for it to take hold!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •