hyptothetical question, safe to swim with FC 12ppm?

smooth2222

LifeTime Supporter
Oct 26, 2010
284
michigan
#1
if your CYA is 100, accoring to the chlorine/CYA chart

CYA 100, Minimum FC 7, Target FC 12,

is it safe to swim with a FC of 12 with CYA at 100?


cause the CYA is locking up a large part of the chlorine?
 

JasonLion

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May 7, 2007
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#2
Yes, and yes. However, you really ought to lower your CYA level, particularly because the common CYA tests will report any level above 100 as if it was 100. So your actual CYA level could be far higher than 100.
 

smooth2222

LifeTime Supporter
Oct 26, 2010
284
michigan
#3
was just a hypothetical question, CYA is at 65-70, duing a drain right now so i can get it even lower.

originally came from 110 CYA, diluted test 50/50 to get accurate 110.

1/3 drain to get to 65-70, doing another 1/3 drain to get it too 40-50



wouldn't a FC of 12 be bad to swim in?
 

JasonLion

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#4
It all depends on the CYA level. With CYA around 100, an FC of 12 is a far lower active chlorine level than you would see in the typical indoor pool (because the CYA has most of the chlorine bound up and inactive at any given moment). If CYA was zero then an FC of 12 would be a serious problem and getting into the range where you could damage the pool as well as the people.
 

smooth2222

LifeTime Supporter
Oct 26, 2010
284
michigan
#5
complete newbie question here.

so why worry about CYA if you just have higher chlorine levels?

since its safe to swim with higher FC if most of it is bound up in the CYA?


thanks for entertaining my questions. you are teaching me and helping me understand.

I know there is an answer to the question which you will tell me in the next post. lol :)

appreciated too
 

JasonLion

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#6
Briefly, CYA that is too low means you will need huge amounts of chlorine to maintain any chlorine in the water at all. CYA that is too high means you will have a very rough time shocking the pool should you ever get algae. Somewhere in the middle is the CYA is just right level (30 to 50 for most pools). There are several additional problems/challenges when CYA is 100+ that are too complex to go into here.
 

smooth2222

LifeTime Supporter
Oct 26, 2010
284
michigan
#7
ya, as you see on my other thread poll figur'ing out the best CYA to get,

pool is almost 1/3 drained for 2nd round, so i should fall around CYA 40-45 area.


Live in michigan, pool is open about 5 months.

thanks
 

JasonLion

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May 7, 2007
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#8
Running a poll won't tell you the best CYA level for your pool. Just the average of what lots of different people happen to do, which isn't even close to the same thing. The truly ideal CYA level varies depending on several factors, SWG or not, amount of sunlight on the water, etc.
 

smooth2222

LifeTime Supporter
Oct 26, 2010
284
michigan
#9
well what do you think? I live in michigan, when its Sunny i'll get 70% of the daily sun.

after this fill up my CYA will be between 40-50, hoping closer to 40-45,

gonna be 1 nice water bill. lol, about 10,000 gallons of water total
 

JasonLion

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May 7, 2007
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#10
Try whatever CYA level you end up at, and see how much chlorine you use on average. If it averages more than 2 ppm per sunny day, add a little more CYA.