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Thread: Black Algae

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    Black Algae

    Hey Guys - I have black algae. I have just pressure washed the areas, now raised it up to 40FC and plan to keep it like that for 24 hours. Its been high cholorine levels for a bit too, so the rest of the algae is dead.

    I also bought some Super Black Algaecide - should I hold the pool at 40 for 24 hours, then bring back down to a normal level before adding black algaecide?

    Thanks

    Lee

    oh...

    13500 gal
    FC - 14 (pressure washed areas then added 3.5 gallons bleach)
    CYA - 70
    salt water pool

    Thanks!
    15'x30'x4' avg, 13,500 gal, IG plaster, 1 HP Hayward pump, Hayward EC65/75 sqft cartridge filter, 1.5" piping, (pool girl on occasion) replaced by Tigershark QC, borates!

  2. Back To Top    #2
    svenpup's Avatar
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    Re: Black Algae

    You should finish a SLAM. There is no magic to 24 hours. You need to maintain the shock FC level until you pass all the criteria including no visible algae. Brush frequently throughout the SLAM.

    Return the algaecide. It is not needed.
    TFP Method Advanced Intermediate
    • 17,500 gallons - In Ground - Plaster - Hayward Swimclear 3020 Cartridge Filter - Sta-Rite Max-E-Glas Main Pump upgraded with A.O. Smith B2980 E-Plus New Centurion Two-Speed Motor - Polaris 280 Cleaner with Polaris PB4-60 Booster Pump - TightWatt2 Timer - Taylor K-2006 Test Kit - Pool Pilot Digital Nano SWCG

    Helpful Links: Pool School, BBB for Beginners, How to Shock (hint...it's a process not a product), Chlorine/CYA Chart, Jason's Pool Calculator

  3. Back To Top    #3

    Re: Black Algae

    Will the SLAM take care of the black algae? Also looks like I need to refinish pool, this is where the big spots are.

    I was planning on adding borates once this is under control - but it doesn't look like much is happening, although the pressure washing removed a lot and hoping that will allow the chlorine to kill the ablack algae.
    15'x30'x4' avg, 13,500 gal, IG plaster, 1 HP Hayward pump, Hayward EC65/75 sqft cartridge filter, 1.5" piping, (pool girl on occasion) replaced by Tigershark QC, borates!

  4. Back To Top    #4
    svenpup's Avatar
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    Re: Black Algae

    The key to eradicating the black algae is maintaining shock level and frequent brushing.

    Check put http://www.troublefreepool.com/content/180-Black-Algae for more information.

    Once you get rid of it, you can prevent it from returning by never allowing FC to drop below minimum for your CYA level.
    TFP Method Advanced Intermediate
    • 17,500 gallons - In Ground - Plaster - Hayward Swimclear 3020 Cartridge Filter - Sta-Rite Max-E-Glas Main Pump upgraded with A.O. Smith B2980 E-Plus New Centurion Two-Speed Motor - Polaris 280 Cleaner with Polaris PB4-60 Booster Pump - TightWatt2 Timer - Taylor K-2006 Test Kit - Pool Pilot Digital Nano SWCG

    Helpful Links: Pool School, BBB for Beginners, How to Shock (hint...it's a process not a product), Chlorine/CYA Chart, Jason's Pool Calculator

  5. Back To Top    #5

    Join Date
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    Re: Black Algae

    You are going to have to REALLY brush that algae. In fact, I recommend a steel brush since you have plaster.

    Black algae loves rough spots in plaster.
    Built in 1957 44,000 gallon in-ground, Wet Edge Primera Stone in Sky Blue, Intelliflo VF Pump, 600 lb. Pentair Triton II TR-100 Sand Filter, CircuPool RG 60 Plus SWG, TF-100 test kit
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  6. Back To Top    #6

    Re: Black Algae

    I spent an hour or so with a pressure washer knocking it out. I should get a steel brush tomorrow too.

    Anyone want to fly down stay in my house and refinish the pool?
    15'x30'x4' avg, 13,500 gal, IG plaster, 1 HP Hayward pump, Hayward EC65/75 sqft cartridge filter, 1.5" piping, (pool girl on occasion) replaced by Tigershark QC, borates!

  7. Back To Top    #7

    Re: Black Algae

    I forgot to test last night after adding the bleach to bring the FC up to 40, but did add the amount required to get it to there.

    This morning it's back down to 21! That seems like a drastic drop, is that common?

    Thanks!

    - - - Updated - - -

    Also, I am not sure where I got the FC of 40 from for the black algae for 24 hours, I swear I read that on here.

    Am I supposed to be aiming for an FC of 40 with a swg and 70 CYA, or just an FC of 28?
    15'x30'x4' avg, 13,500 gal, IG plaster, 1 HP Hayward pump, Hayward EC65/75 sqft cartridge filter, 1.5" piping, (pool girl on occasion) replaced by Tigershark QC, borates!

  8. Back To Top    #8
    svenpup's Avatar
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    Re: Black Algae

    A drop like that is indicative that you needed to shock and the FC is doing its job. 28 is your shock level, but 40 is the mustard algae level for CYA 70. If it were me I would keep targeting 40, at least until the demand goes down.
    TFP Method Advanced Intermediate
    • 17,500 gallons - In Ground - Plaster - Hayward Swimclear 3020 Cartridge Filter - Sta-Rite Max-E-Glas Main Pump upgraded with A.O. Smith B2980 E-Plus New Centurion Two-Speed Motor - Polaris 280 Cleaner with Polaris PB4-60 Booster Pump - TightWatt2 Timer - Taylor K-2006 Test Kit - Pool Pilot Digital Nano SWCG

    Helpful Links: Pool School, BBB for Beginners, How to Shock (hint...it's a process not a product), Chlorine/CYA Chart, Jason's Pool Calculator

  9. Back To Top    #9

    Re: Black Algae

    OK - used the last of my bleach last night (I think the bleach itself may not actually be 10%???) to bring FC up to 16.5, this morning is at 16, less than 0.5 CC. However there's still black algae on the bottom of the pool. Will scrub again today, do I take back up to SLAM levels?
    15'x30'x4' avg, 13,500 gal, IG plaster, 1 HP Hayward pump, Hayward EC65/75 sqft cartridge filter, 1.5" piping, (pool girl on occasion) replaced by Tigershark QC, borates!

  10. Back To Top    #10

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    Re: Black Algae

    Yes, with black algae you need to continue the SLAM process.

  11. Back To Top    #11

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    Re: Black Algae

    Take a look at the black algae how to again. This is not an overnight process.

    http://www.troublefreepool.com/content/180-Black-Algae
    TFP Moderator Chris V. ~16K Pool & Spa, 48NSF DE, IG Plaster Circa 2000, Intermatic PE653, Challenger pump with a 2 speed B2984, 20gal stenner chlorine injection, Houston, TX
    One cannot follow Islam and Christianity at the same time, nor can one follow pool store methods and TFP at the same time.
    Pool School -- Pool Math -- TF-Test Kit

  12. Back To Top    #12

    Re: Black Algae

    thanks guys, keeping it high and its dissipating slowly.
    15'x30'x4' avg, 13,500 gal, IG plaster, 1 HP Hayward pump, Hayward EC65/75 sqft cartridge filter, 1.5" piping, (pool girl on occasion) replaced by Tigershark QC, borates!

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