Can I ever get .5CC down to zero?

[Garet Jax]

Hello all,

I am in the process of shocking my water. Here are my measurements:

TA 80ppm
CH 140ppm
CYA <20ppm but >0ppm
pH 7.5ppm
FC 11ppm
CC .5ppm

The CC has fluctuated between .5 and 1.0 over the last couple of days, but I have never seen it go to 0. Will I ever see that?

 

[Stuamurr]

in an outdoor pool you should see 0.0ppm CC with no or very little use, indoor pools rarely/if ever goto 0.0ppm CC
If your CC's are higher than 0.5ppm you need to shock your pool to get rid of the CC's, because you said you have fluctuated between 0.5 and 1.0ppm CC over the last few days, was there something significant that occurred? A pool party or did you allow the FC level to drop significantly? I ask because your FC now is 11.0ppm if this was maintained throughout the period of testing I find it doubtful that CC's would rise/fluctuate so much, and by all likelihood should of reduced CC to hold lower than 0.5ppm

Regards
Stuart

 

[Richard320]

Eventually you may have a few days in a row where it will read 0. I may show .5 for a week then suddenly get nothing for a few days, then back to .5. Anything organic in the system - whether it's in the pool, or the strainer, or the filter - will create CC.

And Stuart - he IS shocking.

 

[duraleigh]

.5CC and O CC are identical for our purposes.

 

[Garet Jax]

was there something significant that occurred?
Regards
Stuart

Sort of

I was trying the mechanism I bought from the pool store before I found TFP. I spent 80 bucks on it and really didn't want to just throw it away. The water was greenish and I finally said screw it - going to use the test kit and the standard chlorine way. When I did that I noticed my FCs dropped significantly over night and so figured a shock was a good start. That was Monday night so have been shocking since then.

Thanks.

 

[Garet Jax]

.5CC and O CC are identical for our purposes.

I figured as much from what I have read, but am still interested in whether or not it will ever drop to 0.

PS - Love the kit - will probably need more product very soon. I have been working my way through understanding the measurements over the last 5 days and have been having some fun with it.

 

[Stuamurr]

And Stuart - he IS shocking.

Whoops me bad, didn't think about shock level for 20CYA while typing my response!

Well your going in the correct direction then, stick with Pool School and you will see your numbers settle down, given that you've just been at it a few days, your numbers are already doing well.

As Richard stated very well, you will get 0ppm CC from time to time but its not a magical target you should be aiming for, your target should be the OCLT test of 1) Less than 1ppm FC lost overnight, 2) CC of 0.5ppm or less and 3) a clear pool.

P.S. There's nothing to be embarrassed about, everyone is learning the fact you have came to this forum is a big

Regards
Stu

 

[Garet Jax]

Eventually you may have a few days in a row where it will read 0. I may show .5 for a week then suddenly get nothing for a few days, then back to .5. Anything organic in the system - whether it's in the pool, or the strainer, or the filter - will create CC.

And Stuart - he IS shocking.

Very good to know. I took another measurement a few minutes ago and the FC is still 11ppm but the CC has dropped to 0ppm. Looks like it is time for the overnight test

 

[chem geek]

If you are talking about a spa, don't worry about it. Unless you don't use the spa for several days, you won't likely see zero CC and you won't likely see a low chlorine demand. With the hotter water you also won't see <= 1 ppm FC overnight drop if the FC is at a higher shock level. You simply can't compare what goes on in a small spa to what goes on in a large pool. A spa is much more like a commercial/public pool with a high bather load. Also, if the spa is covered, you don't do an OCLT, but rather just look at 24-hour chlorine demand when not using the spa. It should be around 25% FC loss if the water is relatively fresh and you have no ozonator.