Low Fc High Cc

Chlorinating, maintaining the right chlorine levels,
chlorine problems. Dichlor, trichlor, cal hypo, bleach,
granules, chlorine pucks and chlorine sticks.
Yeller
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Low Fc High Cc

Postby Yeller » Mon 31 Mar, 2014 22:17

I tested a friends pool just moved in not long ago. I get 0 FC on sticks and 5ppm of CC so I ran FAS and got 5ppm FC and 30 ppm CC. The CYA is at 65 and pH is fine all else reads ok. Water is clear with no bloom. Will the CC fall or do I need to raise FC ?? We're in Phoenix and it's getting close to 90 degree... Soon the pool temps will be 94 F


chem geek
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Low Fc High Cc

Postby chem geek » Tue 01 Apr, 2014 12:03

Assuming the measurements are correct, you need to add chlorine to get rid of the CC assuming that CC is something simple such as monochloramine. That can happen if there is a bacterial conversion of CYA into ammonia. Usually though one finds that the CYA level has dropped.

You can always experiment in a large bucket where 1/4 teaspoon of 6% bleach in 2 gallons is 10 ppm FC. So you can estimate how much chlorine it will take to get rid of the CC. If you can't get rid of it in the bucket, then you may need to replace the water in the pool, possibly via multiple drain/refill (unless your water table is low in which case a full drain/refill is possible). Hopefully it won't come to that.
Yeller
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Low Fc High Cc

Postby Yeller » Tue 01 Apr, 2014 15:15

Thanks Geek, first I think I may run and OTO and see where the FC comes in at. Thanks for you help. I may into pool supply place and see if they can read Ammonia. Not sure where the appropriate ammonia range is.
chem geek
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Low Fc High Cc

Postby chem geek » Wed 02 Apr, 2014 01:15

If you measure any FC then there isn't any ammonia left because chlorine and ammonia combine to form monochloramine in seconds.

If you do want to test for ammonia there are test kits at fish/pet/aquarium stores but keep in mind that some types of ammonia tests end up measuring monochloramine as well. If you measured the water before adding chlorine, then that would have been the time to measure ammonia. I suppose the ammonia test kit will at least confirm you have monochloramine rather than some other type of CC.

Note also that non-chlorine shock (MPS) can register as CC depending on the test kit.
95690
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Low Fc High Cc

Postby 95690 » Mon 14 Apr, 2014 19:18

Hi chem geek

I sent you a private message.

Thanks

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