Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 5 of 5

Thread: Algae Outbreak

  1. Back To Top    #1

    Algae Outbreak

    So this is the first time since using the BBB method that I've gotten algae and I'm not sure what to do to get rid of it. It is greenish/yellow color algae. On July 4th I tested the water when I first noticed the outbreak and found this:

    FC=3.5
    CC=0
    pH=7.2
    Alk=60
    CH=90 (vinyl pool)
    CYA=100

    I added 3 bottles (182 oz) of bleach and brushed the algea. The pool looked pretty good but cloudy and a greenish tint to the water.

    Today, the algae is back and here are my test results:

    FC=10
    CC=.5
    pH=7.4
    alk=70
    CH=90
    CYA=100

    I'm not sure what to do now. I was thinking about shocking it but wanted to check with you guys first because you have really helped me out over the last few years.
    Thanks
    22000 gallon, vinyl, 1.5HP Century Centurion Pump
    Hayward Sand Filter (no.20 silica sand)
    PoolVac Plus Automatic Cleaner

  2. Back To Top    #2
    frustratedpoolmom's Avatar
    Join Date
    May 2007
    Location
    SWSuburban Chicago, IL
    Posts
    11,963

    Re: Algae Outbreak

    Quote Originally Posted by cmcnitt
    So this is the first time since using the BBB method that I've gotten algae and I'm not sure what to do to get rid of it. It is greenish/yellow color algae. On July 4th I tested the water when I first noticed the outbreak and found this:

    FC=3.5
    CC=0
    pH=7.2
    Alk=60
    CH=90 (vinyl pool)
    CYA=100

    I added 3 bottles (182 oz) of bleach and brushed the algea. The pool looked pretty good but cloudy and a greenish tint to the water.

    Today, the algae is back and here are my test results:

    FC=10
    CC=.5
    pH=7.4
    alk=70
    CH=90
    CYA=100

    I'm not sure what to do now. I was thinking about shocking it but wanted to check with you guys first because you have really helped me out over the last few years.
    Thanks
    With a CYA of 100, that FC level is too low, which would be why you developed algae. On the other hand, CYA tests are not as accurate if you have algae or cloudy water. So was that your CYA before, and are you certain it's accurate?

    If it is indeed accurate, see the CYA Chlorine chart for your recommended targets for minimum and shock level, according to your CYA.

    Also, if it really is 100, you need to do a partial drain and refill of your water, or you will fight a losing battle with algae all season, or spend a small fortune on bleach trying to keep the levels at the recommended point. JMHO.
    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

  3. Back To Top    #3
    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    Location
    SW Indiana
    Posts
    8,618

    Re: Algae Outbreak

    Your chlorine is way too low. With CYA at 100, you should never let your FC get below 7.5ppm.

    Read this article http://www.troublefreepool.com/categ...efeating_algae about algae. High chlorine is the key.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

  4. Back To Top    #4

    Re: Algae Outbreak

    The CYA is usually 100. My FC is at 10 today, how high should I raise it to kill the algea? The chart says 11.4 is the normal target but I'm well within the minimum of 7.3. Should I go to shock levels or the Yel/Mstrd min 14.9? Also, is my pH and alkalinity OK or do I need to adjust it?
    thanks
    22000 gallon, vinyl, 1.5HP Century Centurion Pump
    Hayward Sand Filter (no.20 silica sand)
    PoolVac Plus Automatic Cleaner

  5. Back To Top    #5
    frustratedpoolmom's Avatar
    Join Date
    May 2007
    Location
    SWSuburban Chicago, IL
    Posts
    11,963

    Re: Algae Outbreak

    Quote Originally Posted by cmcnitt
    The CYA is usually 100. My FC is at 10 today, how high should I raise it to kill the algea? The chart says 11.4 is the normal target but I'm well within the minimum of 7.3. Should I go to shock levels or the Yel/Mstrd min 14.9? Also, is my pH and alkalinity OK or do I need to adjust it?
    thanks
    I think they are fine. Yes. To kill regular algae, your "shock" target is good. The Yellow/Mustard is in extreme cases and only for 24 hours or so during the regular shock process. You don't want to maintain FC that high for extended periods, you risk damaging your pool.

    The "normal" target is day to day minimum FC. You do NOT want to let it ever go below that, or as you see with your pool, you may develop algae.
    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

Posting Permissions

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