Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 6 of 6

Thread: Thanks for helping me defeat the terrible algae monster!

  1. Back To Top    #1

    Thanks for helping me defeat the terrible algae monster!

    Hi,

    I want to thank troublefreepool community for helping me fix my pool algae problems. For those interested, here is my story:

    I bought my current house with a pool 2.5 years ago. I had never had a pool before, so I continued using the trichlor pucks that were there when I moved in. I checked pH and chlorine with an OTO test occasionally, and had no problems until last fall when my filter broke while I was on vacation.

    We called the local pool supply store, which sent a tech to fix the filter. The repair didn't get done for a week, we had a bunch of rain storms, and I ended up with algae growing on the walls and bottom. Went to the pool store, and was sold Green to Clean and dichlor shock. This did get rid of the algae. However, even after the filter got fixed the algae came back. I stupidly assumed we just didn't get it all and went back to said pool supply store and got more green to clean and shock. This again fixed algae for week or so, and then it came right back.

    At a high level, I understood why green to clean worked. It contains ammonium sulfate, which promptly reacts with the chlorine from the dichlor shock to give chloramine, which is quite toxic to many living organisms. I understood trichlor and dichlor release HOCl and CYA. I naively assumed that CYA must break down in the pool somehow (pushing a few electrons allows one to draw a hydrolysis of cyanuric acid with 3 moles of water to give 3 moles each of NH3 and CO2).

    I was wrong, of course, but thankfully googling for solutions to pool aglae led me to troublefreepool.com. The excellent chemistry discussions here made it precisely clear why I was having problems: my CYA was so high from years of trichlor and the ill-advised shocking with dichlor that I couldn't get a high enough concentration of HOCl to kill anything. Adding NH3 gave high chloramine levels which worked for a bit, but wasn't a permanent fix. Shame on the pool store people - they should know better.

    At any rate, after measuring CYA with the TFT test kit (around 200) and replacing most of my water I now have CYA at 60 ppm. I shocked with Costco bleach and had FC drop from 24 to 1 in 2 hours, and CC rise up to 12 or so. Clearly lots of stuff to kill. I kept the FC up for a couple days and got things nicely under control (FC stabilized at 12, and CC undetectable after 2-3 days).

    Since then I have easily maintained FC at 5-10 with bleach and have beautiful blue water with no more algae. Thanks to the troublefreepool community for the informative posts, pool chemistry lessons, and the amazing pool calculator.

    Eric
    ___________________________________
    10K gal, plaster, SWG, DE filter, solar heat

  2. Back To Top    #2
    Ohm_Boy's Avatar
    Join Date
    May 2007
    Location
    Orlando, FL
    Posts
    1,344

    Re: Thanks for helping me defeat the terrible algae monster!

    Shame on the pool store people - they should know better.
    They should, but amazingly few of them do.
    [center:1kpalu48]Helpful Links: Pool School | CYA/Chlorine Chart | Pool Calculator[/center:1kpalu48]

  3. Back To Top    #3
    Ohm_Boy's Avatar
    Join Date
    May 2007
    Location
    Orlando, FL
    Posts
    1,344

    Re: Thanks for helping me defeat the terrible algae monster!

    pushing a few electrons allows one to draw a hydrolysis of cyanuric acid with 3 moles of water to give 3 moles each of NH3 and CO2
    I'd like to hijack this thread just a bit to see if this can be explored a bit. We are always seeing folks with unexplained CYA loss. Anyone think there could just be stray electric causes?
    [center:1kpalu48]Helpful Links: Pool School | CYA/Chlorine Chart | Pool Calculator[/center:1kpalu48]

  4. Back To Top    #4

    Re: Thanks for helping me defeat the terrible algae monster!

    Quote Originally Posted by Ohm_Boy
    pushing a few electrons allows one to draw a hydrolysis of cyanuric acid with 3 moles of water to give 3 moles each of NH3 and CO2
    I'd like to hijack this thread just a bit to see if this can be explored a bit. We are always seeing folks with unexplained CYA loss. Anyone think there could just be stray electric causes?
    I apologize for my chemist slang (my day job is as a chemist) which was probably confusing - by 'pushing electrons' I meant that I could draw a plausible mechanism and reaction scheme for breakdown of CYA in water. In the deep end somewhere is a discussion regarding the breakdown of CYA by biological processes. I don't think it happens under normal pool conditions where there is no bacteria growing, and I don't think any electrolysis would help unless it was a pretty big current and/or voltage.
    ___________________________________
    10K gal, plaster, SWG, DE filter, solar heat

  5. Back To Top    #5
    Ohm_Boy's Avatar
    Join Date
    May 2007
    Location
    Orlando, FL
    Posts
    1,344

    Re: Thanks for helping me defeat the terrible algae monster!

    I should apologize for my own ignorance. I won't, but I should.
    [center:1kpalu48]Helpful Links: Pool School | CYA/Chlorine Chart | Pool Calculator[/center:1kpalu48]

  6. Back To Top    #6

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,082

    Re: Thanks for helping me defeat the terrible algae monster!

    Quote Originally Posted by eswayze
    In the deep end somewhere is a discussion regarding the breakdown of CYA by biological processes.
    For reference, the thread is Degradation of Cyanuric Acid (CYA). Though we understand how a fairly rapid oxidation of CYA can occur when the chlorine gets to zero and bacteria can grow and we also understand how CYA can slowly degrade by oxidation from chlorine, we still do not understand why exactly it can decline more rapidly in some pools. Perhaps some catalytic mechanism that accelerates the chlorine oxidation or hydrolysis (oxygen oxidation).
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

Posting Permissions

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