Swim with high CC?

[Team Mel]

Hello, I've been reading the site and studying since last summer when we began to have problems with CC. Frustrated with the pool store, I'm finally ready to take the plunge into the TFP method. I had a CYA of >100 and I drained the pool by half and refilled yesterday. Unfortunately, the CYA still at 100+ so I am going to have drain again before I can SLAM. But, it has been so cold here in Michigan, we finally have some warm weather and the kids are dying to swim. I went to the pool store just to see if they also got a CYA of 100+ because I couldn't believe it was still so high after draining. They confirmed and while I was there they said we could swim even with a CC of 2.0 (they also tried to sell me a CYA removal kit). I was under the impression that CC over .5 was unhealthy for swimmers. I'm planning on draining and refilling again, but I wanted to find out if the kids can swim today? The water is crystal clear, but I have not been able to get rid of the CC. It has been at or above 2.0 for weeks.

Readings with a Taylor K-2006 Test Kit:
FCL: 3.0
CC: 2.0
PH: 7.4
TA: 175
CH: 250
CYA: 100+

Temp: 70

 

[mknauss]

Welcome to the forum!
It can be unpleasant. Red eyes, skin irritation, etc from a high CC.
I would suggest getting your FC at least 10 ppm prior to allowing them to swim.
I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.

 

[mknauss]

Have you added any non-chlorine shock to the pool?

A CC of 2 will make the pool smell of chlorine quite strong. Does it?

 

[JamesW]

Normal ammonia based CC won't persist that long, especially when the pool gets good sunlight.

You probably have something in the water that is creating a CC reading.

Persulfate (ez pool), monopersulfate (non-chlorine shock, MPS), sulfamic acid (Jack's #2) or bromide (yellow out) can all cause persistent CC readings.

Your fc is way too low for the CYA. You need to get the CYA to below 80 ppm.

Then, you need to SLAM to get rid of whatever is in the water.

Make up a sample of 50% pool water and 50% tap water. Mix well and then test the sample for CYA using the normal procedure. Multiply the result by two to get the actual CYA reading.

 

[Team Mel]

Welcome to the forum!
It can be unpleasant. Red eyes, skin irritation, etc from a high CC.
I would suggest getting your FC at least 10 ppm prior to allowing them to swim.
I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.

Yes, I need to raise the FC for sure. I've read most of the site and I'm literally just now trying to put it into action. Thank you so much for the help!

 

[Team Mel]

Have you added any non-chlorine shock to the pool?

A CC of 2 will make the pool smell of chlorine quite strong. Does it?

We did two non-chlorine shocks of MPS a week and a half ago (over two days) and the CC didn't go down at all. We also added some enzyme additive they gave us and, again, no luck. That's one of the reasons we're done with the pool store. They said the MPS won't affect the CC reading after 24 hours. Not sure if that's true or not.

We only get that strong smell when we open the autocover after it's been closed a while. With it open I smell a hint of chlorine, but not much.

 

[mknauss]

The MPS (non-chlorine shock) is most likely still effecting your CC. But it should be gone by the time you complete a SLAM.

 

[Team Mel]

Normal ammonia based CC won't persist that long, especially when the pool gets good sunlight.

You probably have something in the water that is creating a CC reading.

Persulfate (ez pool), monopersulfate (non-chlorine shock, MPS), sulfamic acid (Jack's #2) or bromide (yellow out) can all cause persistent CC readings.

Your fc is way too low for the CYA. You need to get the CYA to below 80 ppm.

Then, you need to SLAM to get rid of whatever is in the water.

Make up a sample of 50% pool water and 50% tap water. Mix well and then test the sample for CYA using the normal procedure. Multiply the result by two to get the actual CYA reading.

Hi James,

Before we added anything, we had a reading of 2.0 CC and even after we added the MPS, it persisted. The pool store told me the MPS will only affect the CC reading for 24 hours. Is that true?

I agree that we definitely need to get the CYA down, but it's still so high after a half drain and refill. Kind of frustrating that I have to do it all over again, but I know I do in order to SLAM. I will definitely try the tap water and pool water test. I'm new to all this so there's been a steep learning curve. Thanks for your help!

 

[JamesW]

I would raise the fc to about 24 and recheck the readings after about an hour.

Tonight, take readings after the sun goes down and again in the morning to see how much chlorine you lose overnight with no sun.