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Thread: CYA => Ammonia - getting FC up

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    CYA => Ammonia - getting FC up

    Hi all-

    Seems like the time of year when I need to lean on everyone's expertise. We just opened our pool, and we had the CYA to Ammonia conversion that others have written about. My numbers yesterday were:

    21500 Gal. outdoor SWG pool
    0 FC
    4 TC/CC
    0 CYA
    6ish ppm Ammonia

    Other chemicals were fine, I added maybe a couple pounds of CYA - not enough to do anything.

    So, over the course of an hour, I added 24 96oz jugs of bleach, 3 182 oz jugs of bleach today, on top of 1 182 oz jug I added yesterday plus my SWG cranking away at 100% all last night.

    Not counting yesterday and the SWG, the pool calculator says that's 63 ppm.

    A couple hours later, I measured, and found this:

    0 FC
    0 TC/CC
    10 (maybe) CYA
    0ish Ammonia (as far as I can tell - I'm between fresh and saltwater, so the default color matches neither card - however, the color never changed from when I put the drops in).

    I cranked the SWG back to 100% and added a few more pounds of CYA (still dissolving).

    Am I on the right track? I read about others getting their FC to stay up over a period of time - with 0 CYA, is "up" 1 FC? Is the chlorine burning off quickly, or is it still eating something in the pool?

    Any tips on where to go from here (other than being patient) are appreciated.

    Regards,
    Michael Risch
    In-ground, vinyl pool, full sun - 23K gallon, Leslies (Hayward) pump, Hayward 60 sq ft (300 lb) sand filter

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    duraleigh's Avatar
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    Re: CYA => Ammonia - getting FC up

    Keep adding the chlorine. That's the only solution.

    One thing you can do to help is add it only in the evening so (because you have so little CYA) you will get maximum use of your chlorine.

    Whether it's eliminating algae, other organics, or the ammonia doesn't really matter......they have to be gotten rid of. Gallons and Gallons of bleach (but not without measuring) is your only path to success.

    I would also turn down your SWG. It is really not capable of helping you obtain the high levels of chlorine that you need and you are shortening the cell life.

    This "shocking" process is best done with chlorine only....save the SWG to maintain your FC when you get done shocking.

    Each gallon of bleach you put in there is helping....you simply must keep going until you can measure some FC that is staying in your pool.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    frustratedpoolmom's Avatar
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    Re: CYA => Ammonia - getting FC up

    Ditto Dave's advice above, when you need to boost the chlorine stick to the liquid so you don't shorten the cell life. You still need more chlorine....keep at it, great progress, way to tackle it head on!
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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    Re: CYA => Ammonia - getting FC up

    The reaction with ammonia, with Combined Chlorine (monochloramine) and with other intermediates that don't register on the test is relatively fast, especially without CYA in the water. If you wanted to know how much chlorine it will take before it starts to register, you can do a bucket test, scaled appropriately. Or you can just keep at it with chlorine since there's not much else you can do other than water replacement.

    In my situation summarized here, there was 0.8 ppm CC and 2 ppm ammonia so theoretically that should have taken around 15 ppm FC to clear, but actually took 56 ppm FC.

    In your case with 4 CC and 6 ammonia, that theoretically takes at least 44 ppm FC to clear, but you may have less intermediates than I had since I sort of caught my CYA-->ammonia conversion "in process". A reasonable estimate could be had if you knew your CYA level when the pool was closed. In that case, it roughly takes 2.5 times the CYA level in FC assuming it all gets converted to ammonia or intermediate products.

    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"

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    Re: CYA => Ammonia - getting FC up

    2.5 times CYA? I'm going to need some more bleach! I had like 70 CYA for the SWG!

    I'm going to see if there is any FC this morning (last year something like this happened, and I was really discouraged, and then all of a sudden I had FC). If it is low, I'm going to go buy more bleach, I guess.
    In-ground, vinyl pool, full sun - 23K gallon, Leslies (Hayward) pump, Hayward 60 sq ft (300 lb) sand filter

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    Re: CYA => Ammonia - getting FC up

    The 2.5 times CYA rule is a worst-case. In practice, some of the ammonia will outgas. A bucket test should tell you how much further you need to go. 1/8th of a teaspoon of 6% bleach in 1 gallon is around 10 ppm FC.
    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"

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    Re: CYA => Ammonia - getting FC up

    On the bucket test, what am I checking every 1/8 tsp? FC? How long do I wait? I've read several posts on the bucket test, but that part has not been clear to me.

    In any event, I just added 8 more 182 oz jugs (33ppm). I did a test in an area that I did not pour the bleach half an hour later, and the strip turned dark purple - way over 10. I'm hoping it wasn't just a bleach spot.

    I also added more CYA today - the batch from yesterday is fully dissolved.

    We'll see what it looks like in 3 hours and in the morning!

    Thanks all for your help.
    In-ground, vinyl pool, full sun - 23K gallon, Leslies (Hayward) pump, Hayward 60 sq ft (300 lb) sand filter

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    JasonLion's Avatar
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    Re: CYA => Ammonia - getting FC up

    You want to make sure the pump is running while you are adding bleach, and for at least an hour afterwards. If you do that, it shouldn't matter too much where you take a water sample for testing.

    There is no need to do a bucket test except to get an estimate of how much more chlorine you are going to need. If you do a bucket test, you should mix throughly after each chemical addition and then give it 30 minutes, or more, to react before testing and adding more chlorine.
    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

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    Re: CYA => Ammonia - getting FC up

    Our pump runs 24 hours a day, and both our filter and our pump are oversized - previous owner's doing. I'll need to get a timer to save on electricity at some point.

    2.5 hours later, and still way up on the FC (dark purple on my strip). CYA appears to be up. I think I am in the clear. I turned the SWG down to 10% (normally runs at 30%). I'll do some detailed measurements tomorrow when some of the FC has burned off.
    In-ground, vinyl pool, full sun - 23K gallon, Leslies (Hayward) pump, Hayward 60 sq ft (300 lb) sand filter

  10. Back To Top    #10

    Re: CYA => Ammonia - getting FC up

    CYA is now 60. Chlorine is still way (dark purple - way more than 10). I turned off the SWG - how long until the excess FC burns off - any thoughts?
    In-ground, vinyl pool, full sun - 23K gallon, Leslies (Hayward) pump, Hayward 60 sq ft (300 lb) sand filter

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    frustratedpoolmom's Avatar
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    Re: CYA => Ammonia - getting FC up

    2-3 days, with the SWG off.

    If you haven't already done so, I highly recommend that you order a good test kit, and stop using the strips, they are very innacurate. You can read about the test kits recommended on this forum in Pool School.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

  12. Back To Top    #12

    Re: CYA => Ammonia - getting FC up

    Thanks - I have a good test kit - I used it for the CYA. It's not cheap, though, especially since I just spent $60 on bleach - so "dark purple" is good enough for me until I'm closer to a chlorine level that I need!
    In-ground, vinyl pool, full sun - 23K gallon, Leslies (Hayward) pump, Hayward 60 sq ft (300 lb) sand filter

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    frustratedpoolmom's Avatar
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    Re: CYA => Ammonia - getting FC up

    With strips, you are basically guessing, and you could be adding too much chlorine, or not enough. I highly recommend you ditch the strips and stick with the FAS-DPD test.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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