Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 10 of 10

Thread: Basic question re: Cl warnings >4 on product labels

  1. Back To Top    #1

    Join Date
    Jul 2010
    Location
    Philadelphia
    Posts
    134

    Basic question re: Cl warnings >4 on product labels

    I am adjusting my pool management based on the information I am finding in here, particularly from pool school and the pool calculator.

    Here is my question based on what manuals and labels are telling me:

    1. Based on my current CYA level, pool calculator suggests 4-8 ppm of FC with shock level of 16. All labels on the chlorinating materials I own, specifically bags of cal-hypo and jugs of liquid chlorine (which I plan to finish off and go with straight bleach btw) state that it is unsafe to swim until the FC drops to 4 again. Is this warning akin to the (bogus) need to cook your meat to 185 degrees? Is there a gov't mandated statement on the safety of FC levels over 4? Do they not take into account any pool having CYA binding much of the chlorine (although the bags of shock recommend CYA in the pool?

    2. The recommended FC level in my goldline aquarite SWG manual is 1-3ppm and that is along with a recommendation that a CYA of 80 is 'best'. That makes no sense to me AT ALL.

    So there is a disconnect between the pool forum(s) and commercial preparations and products.

    What is the scoop?

    Thanks so much!

    Evan
    19000 gal in ground, pebble tec. Sta-rite system 3 DE filter, Aquarite SWG, raypak 406A heater

  2. Back To Top    #2
    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    Location
    SW Indiana
    Posts
    9,089

    Re: Basic question re: Cl warnings >4 on product labels

    Yes there is a disconnect. The missing information is the chlorine/CYA relationship. They treat chlorine as if it is as effective at CYA=0ppm as it is at CYA=100ppm

    Note that CYA levels for SWCGs are different, and the recommended level should be followed.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

  3. Back To Top    #3

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

    Re: Basic question re: Cl warnings >4 on product labels

    You will never see any chlorine product say anything above 4 ppm FC for pools or 5 ppm FC for spas because those are the limits set by the EPA. Unfortunately, this standard is set based on drinking water standards assuming quarts of water drank every day. The standard also does not consider the effect of Cyanuric Acid (CYA) on the active chlorine concentration -- the component that does the sanitizing and oxidation (i.e. the real work). They also do not consider that there is virtually no CYA skin absorption so likely to be minimal from chlorine bound to CYA.

    So while labeling and instructions cannot say anything about higher chlorine levels due to the FIFRA rules from the EPA, many states and local governments allow for higher chlorine levels in public pools and are written into their standards, many allowing up to 10 ppm FC. So even between the government agencies you've got inconsistency.
    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"

  4. Back To Top    #4

    Join Date
    Jul 2010
    Location
    Philadelphia
    Posts
    134

    Re: Basic question re: Cl warnings >4 on product labels

    I suspected something legal was behind it. Thank you for the detailed and very informed responses. It really helps.
    19000 gal in ground, pebble tec. Sta-rite system 3 DE filter, Aquarite SWG, raypak 406A heater

  5. Back To Top    #5
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: Basic question re: Cl warnings >4 on product labels

    Regulatory gibberish. I can buy a gigantic bottle (a small drum, really) of 200mg ibuprofen at any drug store, but I can't take more than 2 at a time. Unless my doctor prescribes it, then I can buy 800 mg tablets. Get real.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

  6. Back To Top    #6

    Join Date
    Jul 2010
    Location
    Philadelphia
    Posts
    134

    Re: Basic question re: Cl warnings >4 on product labels

    So the follow up question is this. Is there an unsafe level, when accounting for CYA, above which there should be no bathers? eg, in my pool the shock level is 16 and it would take a good long while for that to drift down again to the 4-8 maintenance level.

    I want to make sure I am not endangering the kids or pets. Me? I don't care much

    Evan
    19000 gal in ground, pebble tec. Sta-rite system 3 DE filter, Aquarite SWG, raypak 406A heater

  7. Back To Top    #7
    svenpup's Avatar
    Join Date
    Nov 2009
    Location
    Sacramento, CA
    Posts
    835

    Re: Basic question re: Cl warnings >4 on product labels

    Anything below shock level for a given CYA is OK, but you wouldn't want to swim while you are actually in the process of shocking.
    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

  8. Back To Top    #8
    Isaac-1's Avatar
    Join Date
    May 2010
    Location
    SW Louisiana
    Posts
    6,711

    Re: Basic question re: Cl warnings >4 on product labels

    One thing to keep in mind is those instructions on the backs of the commercial products have not changed in 30+ years.

    Many still just suggest having "some" stabilizer in the water with little effort to quantify it or even mention the concept of over dosing it.

    Most of the better test kits you can find on local store shelves don't even offer a test for CYA and those that do (mostly strips) have such crude resolution to be nearly useless.
    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
    I use and endorse TFtestKits TF-100 from http://tftestkits.net
    ~Remember TFP counts on your donations to keep this site ad free~

  9. Back To Top    #9

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

    Re: Basic question re: Cl warnings >4 on product labels

    Quote Originally Posted by shacke
    So the follow up question is this. Is there an unsafe level, when accounting for CYA, above which there should be no bathers? eg, in my pool the shock level is 16 and it would take a good long while for that to drift down again to the 4-8 maintenance level.

    I want to make sure I am not endangering the kids or pets. Me? I don't care much :)

    Evan
    Evan,

    As svenpup wrote, anything up to shock level is generally considered to be OK on this forum. The normal shock level (which is an FC that is roughly 40% of the CYA level) is roughly equivalent to a pool with 0.6 ppm FC and no CYA. Even at the higher yellow/mustard algae shock level (which is an FC that is roughly 60% of the CYA level) this is roughly equivalent to a pool with 1.4 ppm FC and no CYA. (Even assuming 90ºF water with a worst-case temperature dependence these are equivalent to 1.1 and 2.1 ppm, respectively.) So these are generally less than found in most indoor pools that don't have any CYA in them. It's not something you'd want to swim in all the time unless you don't mind the extra wear on swimsuits, skin and hair, but it's not unsafe for infrequent exposure. Inhalation exposure, including disinfection by-products, will be proportional to these lower effective FC equivalents with no CYA.

    Since there is minimal skin absorption of CYA, so likely to be minimal absorption of the chlorine bound to CYA, the main risk for the high FC is direct ingestion of the water through the nose and mouth. The EPA limit of 4 ppm FC per day assumes 2 quarts per day of drinking water so you would not want to drink large quantities of pool water on a regular basis. Probably the worst practical exposure would be gulping the water into the lungs but again would mostly be a problem for frequent occurrences.

    So what is a truly unsafe level? Very hard to say, but would be a lot higher than one would normally achieve when one has CYA in the water. It's a lot easier to get to levels that you smell and may be irritating when there is no CYA in the water. 20 ppm FC with no CYA gives a clear eye irritation in rabbits, for example. Basically, you will get smells and irritations long before you reach anything that is truly unsafe from a one or few time exposure.

    Richard
    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"

  10. Back To Top    #10

    Join Date
    Jul 2010
    Location
    Philadelphia
    Posts
    134

    Re: Basic question re: Cl warnings >4 on product labels

    Thanks, Richard for the detailed and very informative response.

    Evan
    19000 gal in ground, pebble tec. Sta-rite system 3 DE filter, Aquarite SWG, raypak 406A heater

Posting Permissions

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