High Combined Chlorine

[jake_12]

Hi There! First post as I’m somewhat baffled but always appreciate the info here at TFP forums so thought I give it a shot. I think I know the answer but wanted the experts to weigh in.

Recently my combined chlorine has gone from 0 to 3 and I’m not sure why. Water is clear, bright, no debris, algae or any other signs of concern. Not even a smell but it is an outdoor pool. My only conclusion is that there is a potential algae bloom I cannot see but I don’t believe this would create such a high CC. The weather here has turned from relatively mild to blistering hot in short order. Going from the 90’s to over 110. Filter is clean, pool is brushed, maintain chlorine levels in accordance with CYA level. Alkalinity is relatively low but the pool is less than 2 years old

I believe the solution is to SLAM and I have a Taylor FAS-DPD kit on the way. I’ve been adding liquid 12.5% and running the filter essentially non stop to aerate and and better oxidize and it seems to be coming down slightly, but it’s been 3 days now without much change.

Should I continue on as is or SLAM over the weekend? Water balance below

Taylor K2005
PH 7.6
FC 8
CC 3
CYA 50
TA 70
CH 300

 

[PoolStored]

CC >=1 Means SLAM.

 

[PoolStored]

Oh, and Welcome to TFP!!!

 

[jake_12]

Oh, and Welcome to TFP!!!

Lol, thank you glad to be here! Figured SLAM was the answer

 

[Bperry]

Lol, thank you glad to be here! Figured SLAM was the answer

Have you used any non-chlorine shock lately?

 

[jake_12]

Have you used any non-chlorine shock lately?

None at all. Liquid only since I’ve had the pool and been following TFP. Never have had this problem. Only other thing I can think of is I’ve had probably 5 frogs in the pool the last couple of weeks. Not sure that would matter but just throwing reasons out there. Also, just light swimming no big pool parties or little kids, anything like that.

 

[PoolStored]

How old are your reagents?

 

[Jaked35]

So if you're using Taylor k2005 you are not using FAS-DPD so how do you plan on SLAMing the pool?

 

[jake_12]

How old are your reagents?

Ordered from Amazon in August 22 so almost a year but who knows how long they were stored prior to that. I actually had my local pool supply test my water because I didn’t trust the reagents but they showed a CC of 3.5 while I showed 3. So I assume they are still good.

Interestingly enough I tested again just now and CC is showing at 1, so who knows. I’ve been trying to keep my chlorine at the upper level of 9ppm and running my filter 24/7. My previous test from my original post was from this morning so maybe sunlight and aeration are doing their thing

 

[jake_12]

So if you're using Taylor k2005 you are not using FAS-DPD so how do you plan on SLAMing the pool?

You missed the part where I said a FAS-DPD kit is on the way

 

[PoolStored]

When you get your FAS-DPD, retest CC.

 

[jake_12]

When you get your FAS-DPD, retest CC.

For sure. Thanks for your help!

 

[Jaked35]

You missed the part where I said a FAS-DPD kit is on the way

Cool lol, that's what I had to do. I ordered the k2005 based on advice from a YouTuber before I found TFP.

 

[jake_12]

Cool lol, that's what I had to do. I ordered the k2005 based on advice from a YouTuber before I found TFP.

Same. You have the best name ever by the way

 

[PoolStored]

Same. You have the best name ever by the way

Nah...PoolStored is better...

 

[Jaked35]

This is what I was wondering if when you add the 5 drops of R-0003 and invert if you are checking the color match immediately? Because the longer you wait the darker it gets. Please forgive me if you already know this and it seems like a stupid question.

Nah...PoolStored is better...

 

[jake_12]

This is what I was wondering if when you add the 5 drops of R-0003 and invert if you are checking the color match immediately? Because the longer you wait the darker it gets. Please forgive me if you already know this and it seems like a stupid question.

No, not stupid at all. I do check it right away. It’s just odd to me that my water has been great for 2 years then a sudden change. Strange times

 

[Bperry]

This is what I was wondering if when you add the 5 drops of R-0003 and invert if you are checking the color match immediately? Because the longer you wait the darker it gets. Please forgive me if you already know this and it seems like a stupid question.

Color match?

 

[wireform]

R-003 is the reagent you use to check the CC just after the chlorine test which is the fas-dpd test. If your talking about the comparator block for testing the chlorine then you would use the R-0600 which will only show chlorine or no chlorine but a far cry from knowing how much chlorine is there.

 

[Jaked35]

He is using a k-2005 so using R-0003 for CC test in comparator box after test FC add 5 drops and compare color immediately. Correction: sorry it's TC and then subtract for CC