Does sunlight cause CC?

Shane1

LifeTime Supporter
Apr 29, 2010
621
Buckeye, AZ 85326
Will UV rays cause CC?
My CC is 1 it's usually 0. The pool is getting sun all day, sun up to sun down. Light swimmer load, water looks great and no foul smells.
According to pool school I'm keeping my FC to low, but these number have been solid for the last three weeks with the exception of the TC & CC readings I took tonight :? . :hammer:

Here are my numbers
FC 3
TC 2
CC 1
pH 7.6
TA 100
CH 200
CYA 40
Thanks
 

JasonLion

TFP Expert
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May 7, 2007
37,880
Silver Spring, MD
Sunlight helps eliminate CC.

You can't have TC at 2, FC at 3 and CC at 1 all at the same time. TC = FC + CC. That can also be written CC = TC - FC. So either TC is 4, or something more confusing is wrong.
 

Butterfly

TFP Expert
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May 30, 2007
10,045
South Carolina
Because of your location and full sun all day, you may want to increase your CYA to at least 50. :sun:

After you clarify your test results, if you determine your CC is 1, you will need to shock your pool.
 

257WbyMag

TFP Expert
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Feb 23, 2008
5,061
Denton, TX
Butterfly said:
Because of your location and full sun all day, you may want to increase your CYA to at least 50.
I agree with that too. I was thinking that CYA was maybe a little low for an AZ pool.
 

Shane1

LifeTime Supporter
Apr 29, 2010
621
Buckeye, AZ 85326
Thanks for your help.
Yeah something is fouled for sure. I'll get some new data.
As far as the CYA, I was thinking the Trichlor pucks would raise it by now but it hasn't? It's holding at 40.
 

JasonLion

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May 7, 2007
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The CYA test is not at all good at measuring small changes in CYA. Trichlor adds CYA relatively slowly, so it could easily not have changed CYA enough to show up on the test reliably, even though CYA did go up.
 

Shane1

LifeTime Supporter
Apr 29, 2010
621
Buckeye, AZ 85326
Thanks Jason.

I tested again this morning and got these chlorine numbers. No CC but the numbers are low. I added a puck to the floater. I have several remnants in the floater. Do you all know if the pucks are effective till they are totally disolved?
Also can I use BBB without the Borax? The way I read it I can use muriatic acid & aeration as a substitute.
FC 2
TC 2
CC 0
Thanks again for all your help
 

poolgirl22

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Apr 14, 2010
595
Stephens City, VA
Yes. BBB isn't so much about the specifics of the Bs, but a method of consistent testing and knowing what your pool needs, why, what effects chemicals will have and anticipating what your pool will need based on different factors.

I don't use borax because my dogs think the pool is their personal water dish. I try to discourage it but I won't use the borax just in case.
 

JasonLion

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May 7, 2007
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Using borax to raise the PH and adding borates to between 30 and 50 ppm are totally different things. Using borax to raise PH will never reach a borate level that is anywhere near as high as what you get when adding borates. Still, you can skip borax if you want and use soda ash/washing soda instead. Adding borates to between 30 and 50 has always been completely optional.
 

poolgirl22

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LifeTime Supporter
Apr 14, 2010
595
Stephens City, VA
Thanks Jason for that. After I clicked submit, I got to thinking about the borax for the ph adjustment rather than the feel good part. I DO have some on hand in the event I may need it for the PH.
 

geekgranny

LifeTime Supporter
Aug 20, 2009
1,358
North Central Texas
257WbyMag said:
Butterfly said:
Because of your location and full sun all day, you may want to increase your CYA to at least 50.
I agree with that too. I was thinking that CYA was maybe a little low for an AZ pool.
It's getting hotter (it hasn't made it to the predicted 100 today) and very blazingly sunny here it Texas. No cover, water getting up to 87-88 range during day (no heating) and falls to 84 at night. Both figures will rise when we really get into summer.

Two weeks ago I raised my CYA from ~40 to ~50. Chlorine dropped less during day. Earlier in the week I raised it again to ~60. Chlorine dropping even less during day even though it is getting hotter and sunnier. I was surprised that it made such a difference. This is my first summer using BBB method as I converted from Ionization to BBB late last summer. Kept pool open or semi open all winter with water always balanced, and water circulating, even when we had an unusual BIG Freeze and one inch of ice on pool. There hasn't been a speck of algae since I converted AND I REFUSE TO LET IT HAPPEN, now that I know how to properly manage the pool. :whoot:

For my pool I'm going to have to really stay on top of the CYA as I have to backwash and dogs splash out and carry out, on their coats, a lot of water. I'm figuring I'll be adding CYA every couple of weeks, but that is perfectly fine as it is so easy to do and relatively inexpensive. Inexpensive considering how easy it is to keep the FC levels pretty stable and far less worry and testing. I've just about got it down to an estimate how much bleach to add without consulting The Calculator every day. That is, normal pool usage, I can put enough bleach in guesstimating to keep it always above target range but don't overshoot it much. When pool is more heavily used I do check it more, though.

Thanks TFP. gg=alice
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,082
San Rafael, CA USA
Shane,

Are you using a FAS-DPD chlorine test kit such as in the TF-100 or the Taylor K-2006? It sounds like you might be using a DPD test and that's not always easy to tell a 1 ppm CC from a 0.5 ppm CC. I wouldn't fret about CC unless it was obviously high in a DPD test, or more than 0.5 ppm using a FAS-DPD test. And no, sunlight does not cause CC. If anything, the UV in sunlight helps to break down some types of CC.

Richard
 

Shane1

LifeTime Supporter
Apr 29, 2010
621
Buckeye, AZ 85326
Thanks again for the replies. Geekgranny it sounds like you and I are pretty much in the same boat. Richard I'm using a DPD test.
This really is one of the most helpfull forums I've ever seen. :cheers:
 

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