Chlorine level not coming down - do I really want 80ppm CYA

Chlorinating, maintaining the right chlorine levels,
chlorine problems. Dichlor, trichlor, cal hypo, bleach,
granules, chlorine pucks and chlorine sticks.
shacke
Pool Newbie
Pool Newbie
Posts: 4
Joined: Sun 27 Jun, 2010 13:05
My Pool: SWG, 19000 gal, painted plaster, DE filter
Location: Philadelphia

Chlorine level not coming down - do I really want 80ppm CYA

Postby shacke » Sun 04 Jul, 2010 10:04

My CYA level is currently 40. My goal was to bring it to 80 and when that is done, correct the high TA (runs at 130), add borates and run the SWG less to keep the continually rising pH in check (I have mildly scaling).

My pool does not get a lot of sunlight even though it is outdoors and doesn't get much of a bather load - although I can tell you that without CYA my chlorine level is hard to keep up.

Here is my question. At the moment, my TC level is 10.5 down from 12.0 3 days ago when I overshocked it and shut the SWG to let it drift down. It's been in the 90s here too. If I raise the CYA level to 80, after a routine shock - will it take 'forever' in my case to come back down to safe, swimmable FC levels - is there an unsafe level actually?

Am I making a false assumption somwhere?

pH 7.3
TC 10.5
CC 0.5
CH 250
TA 130
CYA 40

Thank you for your help.


chem geek
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Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

Chlorine level not coming down - do I really want 80ppm CYA

Postby chem geek » Sun 04 Jul, 2010 19:38

The chlorine may drop more slowly at the higher CYA level. In your situation, it doesn't sound like the higher CYA level of 80 ppm may be necessary since you don't have a lot of sunlight on the pool. Yes, some CYA is needed because having none results in rather rapid chlorine loss, but you might be OK where you are. If you find that your SWG on-time is fairly low and your rate of pH rise isn't too fast, then maybe 40-60 ppm CYA might work for you.
shacke
Pool Newbie
Pool Newbie
Posts: 4
Joined: Sun 27 Jun, 2010 13:05
My Pool: SWG, 19000 gal, painted plaster, DE filter
Location: Philadelphia

Chlorine level not coming down - do I really want 80ppm CYA

Postby shacke » Mon 05 Jul, 2010 10:23

Thanks - and there in lies the trial and error to come. The pH rising is a continual issue for me which is why I am trying to find the sweet spot for my SWG - both in terms of % and run time. I am also awaiting delivery of a cheap fountain so I can try aerate and get the TA down a bit - then add borates - and hopefully find the right combination of chlorine stability and smoother changes in pH

Thanks, chemgeek :thumbup:

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