Become a TFP Supporter Pool Math Forum Rules Pool School
Page 1 of 2 12 LastLast
Results 1 to 20 of 25

Thread: I think I have the start of Black Algae - Black spots on bottom of the pool

  1. Back To Top    #1

    Join Date
    Mar 2015
    Location
    Las Vegas NV
    Posts
    481

    I think I have the start of Black Algae - Black spots on bottom of the pool

    So the other day I noticed I had some small black spots near the pool drains. I thought they were pill bugs as in the spring/summer we get a lot of them and thought when I turned on my vac this week (try and vac pool once a week) and it would pick them up.

    So pool vac ran today and the spots are still there. Grabbed my nylon brush move them around and I could only get say 1 out of a dozen to move. They're black spots on my plaster. My FC is always in recommended range, however, during the winter I haven't brushed the bottom of the pool regularly (did not "close" pool).

    Spots are in the deep end, water is 42 so I'm not jumping in to scrub, so it looks like I'll get a stainless brush and try and brush the spots 7' underwater. Any suggestions other than what I found here - Pool School - Black Algae

    Wish me luck!
    SUMMER 2015 BUILD IG gunite 38 x 31, 28,000 gal, 110' perimeter, Intelliflo VS, Whisperflow 3hp, Intellibrite LED x2, Clean & Clear 520, Screen Logic, Intelichlor 40, Quartzscape Blue, K-2006C, Speedstir, Maytronics Dolphin Nautilus Cleaner

  2. Back To Top    #2
    Mod Squad kimkats's Avatar
    Join Date
    Jul 2012
    Location
    Tallahassee, FL
    Posts
    33,883

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    OH no! I KNOW you have kept your levels balanced! I wonder if you can rig up a way to put a puck on top of one of the spots? maybe in a holey bag like mesh? That way you can get it in and out without getting in the burrrrr your self!

    Kim
    TFP Moderator 33x52 round AG 25,600 gals Sand Filter 1.5hp Pump - 2 Speed, SLAM, Pool School, Recommended Levels, Recommended Chemicals, Pool Math, Chlorine/CYA Chart, TF-100 Test Kit

  3. Back To Top    #3

    Join Date
    Mar 2015
    Location
    Las Vegas NV
    Posts
    481

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    Yea it's a drag. Got a couple more spots up so I'm going to keep brushing twice a day for a week and see if the come loose.


    SUMMER 2015 BUILD IG gunite 38 x 31, 28,000 gal, 110' perimeter, Intelliflo VS, Whisperflow 3hp, Intellibrite LED x2, Clean & Clear 520, Screen Logic, Intelichlor 40, Quartzscape Blue, K-2006C, Speedstir, Maytronics Dolphin Nautilus Cleaner

  4. Back To Top    #4

    In the Industry

    FloridaSolarPro's Avatar
    Join Date
    Oct 2011
    Location
    Fort Myers, FL
    Posts
    49

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    A heavy dose of granular algaecide worked for me.

    Jason Szumlanski
    Vice President
    Fafco Solar

  5. Back To Top    #5
    Mod Squad kimkats's Avatar
    Join Date
    Jul 2012
    Location
    Tallahassee, FL
    Posts
    33,883

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    Quote Originally Posted by FloridaSolarPro View Post
    A heavy dose of granular algaecide worked for me.

    Sent from my SAMSUNG-SM-G935A using Tapatalk
    When you say "granular algaecide" what do you mean?

    We have found brushing and chlorine will do the trick without adding unknown stuff to the pool.

    Kim
    TFP Moderator 33x52 round AG 25,600 gals Sand Filter 1.5hp Pump - 2 Speed, SLAM, Pool School, Recommended Levels, Recommended Chemicals, Pool Math, Chlorine/CYA Chart, TF-100 Test Kit

  6. Back To Top    #6

    In the Industry

    Join Date
    Jun 2016
    Location
    Florida
    Posts
    32

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    Pretty sure he means granulated trichlor. Same as rubbing a tab on it, pretty much.

  7. Back To Top    #7
    Mod Squad kimkats's Avatar
    Join Date
    Jul 2012
    Location
    Tallahassee, FL
    Posts
    33,883

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    Not really since you would throw that into the pool where the tab would only be in one spot for a short amount of time.

    Kim
    TFP Moderator 33x52 round AG 25,600 gals Sand Filter 1.5hp Pump - 2 Speed, SLAM, Pool School, Recommended Levels, Recommended Chemicals, Pool Math, Chlorine/CYA Chart, TF-100 Test Kit

  8. Back To Top    #8

    In the Industry

    Join Date
    Jun 2016
    Location
    Florida
    Posts
    32

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    Right. People typically use the granulated version when the problem is more widespread and they don't feel like holding a puck on every spot. Lazy way out.

  9. Back To Top    #9

    In the Industry

    FloridaSolarPro's Avatar
    Join Date
    Oct 2011
    Location
    Fort Myers, FL
    Posts
    49

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    Quote Originally Posted by Dz7 View Post
    Right. People typically use the granulated version when the problem is more widespread and they don't feel like holding a puck on every spot. Lazy way out.
    You mean the lazy way that worked like a charm? Yes, trichlor. The spots were at the end of a swim lane that gets poor circulation because of the pool design. I turned the pump off and used a healthy dose sprinkled right over the area with the spots. 8 hours later I started the pump back up and vacuumed the area. Problem 100% solved the easy way, aka the lazy way I guess.

    Jason Szumlanski
    Vice President
    Fafco Solar

  10. Back To Top    #10

    Join Date
    Dec 2015
    Location
    Hawera, Taranaki, New Zealand
    Posts
    443

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    In my world as long as it works, lazy = efficient
    Oh and I can be very very efficient
    6000 gal, AG vinyl, Intex ultra frame 16ft, 1200 Gallon Sand Filter, DIY Solar, Clear Choice Labs Testing Kit

  11. Back To Top    #11

    Join Date
    Feb 2014
    Location
    Houston, TX
    Posts
    164

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    How high does your fc level need to be when using the trichlor puck on lets say 60 cya?


    Century B129, 3/4 HP, 1.5 SF,
    In-ground gunite 17,400 Gal, FNS plus 60 DE Filter

  12. Back To Top    #12

    Join Date
    Dec 2015
    Location
    Hawera, Taranaki, New Zealand
    Posts
    443

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    Consoleman I would use the non-swg level of targeting 7-9FC and never less than 5 as per the Chlorine/CYA Chart
    6000 gal, AG vinyl, Intex ultra frame 16ft, 1200 Gallon Sand Filter, DIY Solar, Clear Choice Labs Testing Kit

  13. Back To Top    #13

    Join Date
    Feb 2014
    Location
    Houston, TX
    Posts
    164

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    Caco.
    Is it necessary to have the fc levels at shock level when using the rubbing the tricholr on the black algae or can i have them at 7-9?

    Id like to be in the pool when treating the black algae but rather not a shock fc levles


    Century B129, 3/4 HP, 1.5 SF,
    In-ground gunite 17,400 Gal, FNS plus 60 DE Filter

  14. Back To Top    #14

    Join Date
    Dec 2015
    Location
    Hawera, Taranaki, New Zealand
    Posts
    443

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    Consoleman
    I would let the FC drop to 1-2 points below your slam level and then get in the pool
    It is safe to swim at that level
    7-9FC is your daily maintenance level

    So we dont keep hijacking the OP's thread, why dont you start your own thread, and post a full set of test results, so we can give you advice specific to your situation
    6000 gal, AG vinyl, Intex ultra frame 16ft, 1200 Gallon Sand Filter, DIY Solar, Clear Choice Labs Testing Kit

  15. Back To Top    #15

    Join Date
    Mar 2015
    Location
    Las Vegas NV
    Posts
    481

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    UPDATE: I have pneumonia so I haven't been diligent about brushing our getting my son to brush. Wire brush was delivered and son brushed this morning, looked this afternoon and spots are all there but they're lighter, progress? FC is 7, CC is .05
    SUMMER 2015 BUILD IG gunite 38 x 31, 28,000 gal, 110' perimeter, Intelliflo VS, Whisperflow 3hp, Intellibrite LED x2, Clean & Clear 520, Screen Logic, Intelichlor 40, Quartzscape Blue, K-2006C, Speedstir, Maytronics Dolphin Nautilus Cleaner

  16. Back To Top    #16

    Join Date
    Mar 2015
    Location
    Las Vegas NV
    Posts
    481

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    So after a week of brushing with a wire brush spots are still there. Plaster guy coming out to look at it tomorrow.
    SUMMER 2015 BUILD IG gunite 38 x 31, 28,000 gal, 110' perimeter, Intelliflo VS, Whisperflow 3hp, Intellibrite LED x2, Clean & Clear 520, Screen Logic, Intelichlor 40, Quartzscape Blue, K-2006C, Speedstir, Maytronics Dolphin Nautilus Cleaner

  17. Back To Top    #17

    Join Date
    Mar 2015
    Location
    Las Vegas NV
    Posts
    481

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    Plaster guy just left and said it's "organic" Suggested bumping-up FC level and brush, said it would come off. Any suggestions on how high to take my FC?

    Here are my current numbers:
    FC - 6
    CC - .5
    pH - 7.5
    TA - 80 (going to bring this down to 60 AGAIN before I do this)
    CH - 1050
    CYA - 30
    Salt - 3,500
    CSI - .05
    SUMMER 2015 BUILD IG gunite 38 x 31, 28,000 gal, 110' perimeter, Intelliflo VS, Whisperflow 3hp, Intellibrite LED x2, Clean & Clear 520, Screen Logic, Intelichlor 40, Quartzscape Blue, K-2006C, Speedstir, Maytronics Dolphin Nautilus Cleaner

  18. Back To Top    #18

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,941

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    Qingguy,

    First, I am gonna suggest you bump your CYA to 60-70. 30 is too low for the coming Vegas summer and an SWG.

    After that bump, I would bring the FC up to around 15 or so. There is no Magic number but that's a good place to be very effective. That steel brush has to be used, too. Don't erode a hole in your finish but use it often to expose that black algae to the chlorine.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  19. Back To Top    #19

    Join Date
    Mar 2015
    Location
    Las Vegas NV
    Posts
    481

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    Quote Originally Posted by duraleigh View Post
    Qingguy,

    First, I am gonna suggest you bump your CYA to 60-70. 30 is too low for the coming Vegas summer and an SWG.

    After that bump, I would bring the FC up to around 15 or so. There is no Magic number but that's a good place to be very effective. That steel brush has to be used, too. Don't erode a hole in your finish but use it often to expose that black algae to the chlorine.
    Yep, coming out of my winter levels. During the winter I float pucks to maintain 5 FC, doesn't take much and doesn't seem to raise the CYA level at all either. I'll be raising the CYA shortly, not sure if I'll get to it before I shock but soon. Thanks for the tip on the wire brush use.
    SUMMER 2015 BUILD IG gunite 38 x 31, 28,000 gal, 110' perimeter, Intelliflo VS, Whisperflow 3hp, Intellibrite LED x2, Clean & Clear 520, Screen Logic, Intelichlor 40, Quartzscape Blue, K-2006C, Speedstir, Maytronics Dolphin Nautilus Cleaner

  20. Back To Top    #20

    Join Date
    Mar 2015
    Location
    Las Vegas NV
    Posts
    481

    Re: I think I have the start of Black Algae - Black spots on bottom of the pool

    Duraleigh you got me thinking, do you think I should raise my CYA and then slam? This is my first slam btw.

    Do you think I should not worry about lowering my TA until after my slam? I guess I'm needing guidance on order of importance.

    Heres a picture of the spots


    SUMMER 2015 BUILD IG gunite 38 x 31, 28,000 gal, 110' perimeter, Intelliflo VS, Whisperflow 3hp, Intellibrite LED x2, Clean & Clear 520, Screen Logic, Intelichlor 40, Quartzscape Blue, K-2006C, Speedstir, Maytronics Dolphin Nautilus Cleaner

Page 1 of 2 12 LastLast

Posting Permissions

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