Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 7 of 7

Thread: Giardia

  1. Back To Top    #1

    Join Date
    Feb 2012
    Location
    Dallas, Texas
    Posts
    56

    Giardia

    Last week we got a dog from a rescue shelter - cute little puppy. The rescue vet gave her a clean bill of health. Just to be sure we scheduled a visit to our regular vet, which took place Tuesday. Today our vet tols us her stool sample tested positive for giardia.

    She is not sypmtomatic, but the vet put her on antibiotics. Since she's been in our pool I want to do the same with it. Ph is about 7.2, which is supposed to help. But the CDC says to basically shock the pool. So, do I take the pool up to regular or mustard algae shock level? How long should I maintain shock levels? Anything else I should do? We're bleaching and/or throwing away the kids' pool toys, which I hope is overkill, but I don't want to do this again.

    Thanks
    IG plaster pool, 16000 gallons, Hayward DE6020 filter (120GPM) , 2.0 HP 230v single speed 1.3SR motor on Sta-Rite Max-E-Glas 1 pump, Polaris 280 (with Polaris 1.5 HP booster pump), spa.

  2. Back To Top    #2
    Mod Squad zea3's Avatar
    Join Date
    Jul 2009
    Location
    Houston, Texas
    Posts
    9,200

    Re: Giardia

    Copying chemgeek's post from Fecal Accident.

    Quote Originally Posted by chem geek View Post
    Realistically, the only issue with fecal matter is whether it contains protozoan oocysts, specifically Giardia or Cryptosporidium. Without these, any bacteria or viruses will be killed fairly quickly, especially if you've removed physical matter and the rest is dispersed and exposed to chlorine. Unfortunately, the protozoan oocysts are very resistant to chlorine. The official CDC Fecal Incident Response Recommendations for Pool Staff has Giardia with a CT value of 45 and Crypto with a CT value of 15,300. In an SWG pool with an FC that is about 5% of the CYA level, the effective FC level with no CYA is 0.05 ppm. So that means the germ inactivation time to kill 99.9% of Giardia is 900 minutes or 15 hours. For Crypto, it's over 7 months so essentially not killed. This assumes no germicidal effect from the chlorinated cyanurates and that's a reasonable conservative assumption given the CDC data.

    In your current pool with an FC of 6.2 ppm and a CYA of 45 ppm, this is roughly equivalent to an FC with no CYA of 0.1 ppm so a 99.9% kill time for Giardia of around 8 hours (if the water temp were 77F -- yours is colder so kill time would be longer).

    Odds are that unless your pet had diarrhea then it is less likely that it has a protozoan parasite in its fecal matter in large numbers. Also, you'll note that the guidelines assume that formed stools are much less likely to have Crypto. The CDC Annex for Module 6.5 of the Model Aquatic Health Code (MAHC) shown here describes how 300 samples of formed stool fecal incidents in public pools were analyzed and none had Crypto but 4.4% had Giardia.

    If you were to use chlorinating liquid or bleach to raise the FC to the normal shock level of around 40% of the CYA level, then this is equivalent to an FC with no CYA of around 0.6 ppm, assuming you lower the pH before adding the chlorine to prevent the pH from rising too much. That would then kill 99.9% of Giardia in around 75 minutes. Given that this fecal matter was from a dog and not a human and given that it was not diarrhea, you could probably not shock and just wait one day, stay out of the pool, and keep the pump running for 24 hours and then be fine.

    Richard
    I would use normal shock level and maintain it for 24 hours. You can use PoolMath to determine your shock level.
    TFP Moderator
    Helpful links: TF Test Kits,TFP Pool School, PoolMath
    Vogue 21' round AG, Pentair 1 hp 2 speed pump, 36 sq ft DE filter, Hayward S180T 150# sand filter, Houston, Texas
    Love TFP? Become a
    TFP Supporter!

  3. Back To Top    #3

    Join Date
    Feb 2012
    Location
    Dallas, Texas
    Posts
    56

    Re: Giardia

    Quote Originally Posted by zea3 View Post
    Copying chemgeek's post from Fecal Accident.



    I would use normal shock level and maintain it for 24 hours. You can use PoolMath to determine your shock level.
    Fantastic. Thank you.
    IG plaster pool, 16000 gallons, Hayward DE6020 filter (120GPM) , 2.0 HP 230v single speed 1.3SR motor on Sta-Rite Max-E-Glas 1 pump, Polaris 280 (with Polaris 1.5 HP booster pump), spa.

  4. Back To Top    #4
    Casey's Avatar
    Join Date
    Apr 2007
    Location
    SW PA
    Posts
    10,157

    Re: Giardia

    Why can't you throw the kids' toys in the pool and SLAM them too? You could spray the rafts and floaties with a bleach solution. I wouldn't throw the stuff away.
    I'd bet you my bikini you'll never get TFP water from a pool store!

    24' Sharkline Venture De Filter

  5. Back To Top    #5
    Patrick_B's Avatar
    Join Date
    Jun 2011
    Location
    Midland TX
    Posts
    15,001

    Re: Giardia

    Quote Originally Posted by Casey View Post
    Why can't you throw the kids' toys in the pool and SLAM them too? You could spray the rafts and floaties with a bleach solution. I wouldn't throw the stuff away.
    +1

    Drench them in a bleach solution and sterilize them.
    TFP Moderator
    Essential Links:
    ABC's Of Pool Chemistry, Test Kits, SLAM Your Pool
    28K Gal IG FreeForm, CLI Quartz, Pentair 36"SF & VS Pump, Dolphin M5, Rheem

  6. Back To Top    #6
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: Giardia

    It is often good to throw away pool noodles, as they tend to have many nooks an crannies that are good places for bacteria to hide from chlorine. Anything with a smooth surface is easy to clean, so is often worth keeping.
    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

  7. Back To Top    #7
    Casey's Avatar
    Join Date
    Apr 2007
    Location
    SW PA
    Posts
    10,157

    Re: Giardia

    I could see pitching those cheap noodles. I was thinking not so much for diving rings, sticks, goggles and stuff like that. Noodles start to deteriorate after a season or 2 anyway.
    I'd bet you my bikini you'll never get TFP water from a pool store!

    24' Sharkline Venture De Filter

Posting Permissions

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