CC test question

[vanhout]

When I add the 5 drops of the R003, the solution turns a pinkish color, not a solid pink. When I add one drop of the R0871, it goes clear again. So, I'm thinking I have .5 cc.

Is that right? How pink does it get if you have CC? It's not solid pink like it is after adding the powder, and it's not clear. I'd say it's pinkish.

So if I do have .5 cc, I should be shocking, right? I'm at 40-50 CYA, and went up to 15 TC last night, it's down to 10 TC tonite and I still have .5 CC. Do I have to shock and hold to get the CC down? How long might I expect it to take?

Thanks, happy swimming....

[CarlD]

Yes, that's exactly right. You have more than 0.0 CC, but no more than 0.5ppm of CC.

[KurtV]

When I add the 5 drops of the R003, the solution turns a pinkish color, not a solid pink. When I add one drop of the R0871, it goes clear again. So, I'm thinking I have .5 cc.
van,

You can use a 25 cc sample instead of the 10 cc and get a little better precision; 0.2 vs. 0.5. I don't know that it matters that much, but it will give you a little better sense of where your water is.

[vanhout]

van,

You can use a 25 cc sample instead of the 10 cc and get a little better precision; 0.2 vs. 0.5. I don't know that it matters that much, but it will give you a little better sense of where your water is.

When you do the 25 cc method, do you add more than 5 drops of the R0003? How about for the FC measurement - what does each drop of the R0871 equal in terms of FC?

Thanks!

[prh129]

I am interested in getting better accuracy than 0.5 on the CC reading. It would seem to make sense that if you increase the sample size to 25cc and keep the amount of the first FAS-DPD reagent the same, then you could divide the number of drops of FAS-DPD#2 by 5 instead of 2 (since the sample is 2.5 times bigger, you should have 2.5x more chlorine in it so 2.5 x 2 = 5).

I didn't see any response to Kurt's suggestion positive or negative so can anyone confirm that the 25 cc test method is legit?

Thanks

Peter

[KurtV]

When you do the 25 cc method, do you add more than 5 drops of the R0003? How about for the FC measurement - what does each drop of the R0871 equal in terms of FC?

Thanks!

Sorry, I missed this when you posted it.

I should have noted in my first reply that I use a Taylor K2006 instead of Ben's kit (he was between kits when I needed one but I have purchased replacement reagents from him) The K2006, however, uses many of the same reagents and I think the FC test is identical. So, assuming the FC test is the same between the K2006 and Ben's tests (thoroughly mix two scoops of DPD powder into the water sample and then drop and swirl 0871 until the sample goes clear), yes, you will be able to test to the 0.2 ppm level by using a 25 CL sample instead of a 10 CL. With a 25 CL sample, each drop of 0871 will represent 0.2 ppm FC.

Again though, I'm not sure that there is much practical benefit in doing this routinely (or maybe even ever) and it will make you consume 0871 over twice as fast. It also makes the test more time consuming (more drops and swirls).