Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 12 of 12

Thread: Is this black algae?

  1. Back To Top    #1

    Is this black algae?

    I have a question about some staining issues I am currently having. Here are the most recent test results:

    FC 3.5 (bumped it up to 4 last night)
    CC <0.5
    pH 7.5
    T/A 80 (brought pH down last night and aerated)
    CH 310
    CYA 50 (low, I know, added some CYA again. It seems to keep decreasing)

    The last OCLT test about two weeks ago was OK.

    These two pictures are not great, but has been a little breezy the last several days.

    http://i1131.photobucket.com/albums/...deller/107.jpg
    http://i1131.photobucket.com/albums/...deller/106.jpg

    How it started was with one or two spots at the corner of the wall and floor about1" in daimeter, irregular in shape and grey in color. Now there are more appearing as small round dots, dark in color. The chlorine tablet test was inconclusive. However, the increase in number is leading me to believe that this is some kind of black algae. (Of course it is the first week after school ended and the wife doesn't want me to shock the pool just yet, ugh.) My plan is to run the OCLT test tonight and begin shocking after that. Does this sound like an appropriate plan. From reading posts on this I assume I need to rub these spots down with a pumice stone and then shock. Which shock level am I looking for? Pool calc says 16 for normal shock and 29 for mustard algae.
    Pool: Inground gunite/plaster, 34'x12', 3.5' - 5.5' - 3.5', ~14,000 Gal, 420 SQFT, 87.5' Perimeter, Salt Water, Waterfall, Oklahoma flagstone. Equipment: Hayward V/S, 425 SQFT Cartridge filter, Pool Pilot Digital Nano http://www.troublefreepool.com/new-p...tx-t38458.html

  2. Back To Top    #2
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: Is this black algae?

    That doesn't really look like black algae, though sometimes it is difficult to tell. Before shocking, feel a spot and see what it feels like. Black algae will be slimy and you will be able to scrape a little off with your fingernail.
    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

  3. Back To Top    #3

    Re: Is this black algae?

    OK, I didn't think they felt slimy. It started with 1 or 2 and now there are about 6 or so spots. They don't brush off with either the pool brush, wire brush or pumice stone. Is there another test to try?

    While I am at it, there is another issue I am having, but I don't think it is related. A few of the returns have a tan colored stain below them in a fan shape, where the return was exiting. these returns exit through a slit, so push a fan shaped plume of water, directed down. It is more prominent in daylight and does not respond to the pumice stone, at least not that I can see. The below picture does not do it justice. I am thinking scale, but how do I get rid of it?

    Pool: Inground gunite/plaster, 34'x12', 3.5' - 5.5' - 3.5', ~14,000 Gal, 420 SQFT, 87.5' Perimeter, Salt Water, Waterfall, Oklahoma flagstone. Equipment: Hayward V/S, 425 SQFT Cartridge filter, Pool Pilot Digital Nano http://www.troublefreepool.com/new-p...tx-t38458.html

  4. Back To Top    #4
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: Is this black algae?

    Try putting a vitamin C tablet on one of the spots and the brown area for a minute or so. If they are iron stains the vitamin c will clear up the small area it touches.
    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

  5. Back To Top    #5

    Re: Is this black algae?

    JasonLion,

    Thanks for the really quick responses, and the great resource this site is.

    Iron stains? OK I'll try it. Where would the iron come from, the fill water? If they are iron stains, how do I get rid of those?
    Pool: Inground gunite/plaster, 34'x12', 3.5' - 5.5' - 3.5', ~14,000 Gal, 420 SQFT, 87.5' Perimeter, Salt Water, Waterfall, Oklahoma flagstone. Equipment: Hayward V/S, 425 SQFT Cartridge filter, Pool Pilot Digital Nano http://www.troublefreepool.com/new-p...tx-t38458.html

  6. Back To Top    #6
    Butterfly's Avatar
    Join Date
    May 2007
    Location
    South Carolina
    Posts
    10,045

    Re: Is this black algae?

    Quote Originally Posted by adeller
    JasonLion,

    Thanks for the really quick responses, and the great resource this site is.

    Iron stains? OK I'll try it. Where would the iron come from, the fill water? If they are iron stains, how do I get rid of those?
    If you only have a few small spots, you can crush cheap vitamin C tablets in a sock and hold it on the stain for a few minutes.
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

    ~ One should not use a sledge hammer to swat a mosquito. ~

    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  7. Back To Top    #7

    Re: Is this black algae?

    Bingo! Vitamin C did the trick. Thank you again. I didn't think it could possibly be iron. SO the question is, would that be iron from the fill water? If so, what did I do to make it precipitate?
    Pool: Inground gunite/plaster, 34'x12', 3.5' - 5.5' - 3.5', ~14,000 Gal, 420 SQFT, 87.5' Perimeter, Salt Water, Waterfall, Oklahoma flagstone. Equipment: Hayward V/S, 425 SQFT Cartridge filter, Pool Pilot Digital Nano http://www.troublefreepool.com/new-p...tx-t38458.html

  8. Back To Top    #8
    Melt In The Sun's Avatar
    Join Date
    Oct 2009
    Location
    Tucson, AZ
    Posts
    3,899

    Re: Is this black algae?

    Probably not from the fill water since it was just in a couple spots. More likely it was from something that fell in, like a Bobby pin, some ironite fertilizer, of some pieces of metal from you nextdoor neighbor's angle grinder.
    11,200 gal, Pebble-Tec; Tristar 2-speed 1hp - Swimclear 325 ft2 cart - SWG - A & A in-floor cleaner - Heat pump. For the poolside cooking, a Yoder Wichita and a Big Steel Keg!
    TF Test Kits -- PoolMath -- Pool School
    Make each day your masterpiece. - John Wooden

  9. Back To Top    #9
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: Is this black algae?

    A tiny piece of steel can leave a sizeable rust stain. It's amazing, really. After we had a new fence put up, there was the expected dirt, but also tiny pieces of metal - probably broken off nail heads or something. BIG rust spots. A nylon full of Vitamin C and a smooth rock for weight, all tied to a long string, got rid of it.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

  10. Back To Top    #10

    Join Date
    Sep 2009
    Location
    Greentown, IN
    Posts
    914

    Re: Is this black algae?

    Wow.. didn't know a bobby pin could be so problematic. I'll have to ban them from my pool!
    Indiana, ABG 24'x52" Galveston by Blue Cascade (Craigslist buy w/part of deck included), 13,500 gallons, Intex SWG, solar panels mix 2, TF-100 test kit.

    Test kits compared
    Purchase test kits

  11. Back To Top    #11
    linen's Avatar
    Join Date
    Jul 2010
    Location
    Twin Cities, MN
    Posts
    8,649

    Re: Is this black algae?

    Quote Originally Posted by Suziqzer
    Wow.. didn't know a bobby pin could be so problematic. I'll have to ban them from my pool!
    Or just ban swimmers who use them
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

  12. Back To Top    #12

    Join Date
    Sep 2009
    Location
    Greentown, IN
    Posts
    914

    Re: Is this black algae?

    That would work too... Luckily that doesn't include me
    Indiana, ABG 24'x52" Galveston by Blue Cascade (Craigslist buy w/part of deck included), 13,500 gallons, Intex SWG, solar panels mix 2, TF-100 test kit.

    Test kits compared
    Purchase test kits

Posting Permissions

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