Clear, but no chlorine???

[FormerBromineUser]

Not that I'm an expert, but... You can use the patented CarlD shot glass dilution method of chlorine testing to get a start this weekend. Mix 5 shot glasses of distilled water with one shot glass of pool water then test the mix for chlorine and multiply by 6. Not accurate enough to know when your done but good enough to start the shock process.

You intended those instructions for the weekend only (when she was out of 0871).

Also, I believe she bought the 16oz bottle so she should be good even with the 10ml sample.

If not, Mary Jo, I still have an extra 2oz bottle of 0871 if you need it. I am leaving for VA Saturday morning so you would need to let me know today.

[mary jo]

Oh you must think I'm daft! Yes, FBU got it right: I misunderstood the weekend instructions (diluting at 5:1) to mean continue testing this way until almost done, and since I was going through 50-60+ drops at a time, testing 4-5x a day it made sense….until last night when it occurred to me the exact ppm's lost were getting more critical. That's why I asked about it this morning….I also have been testing each sample more than once to make sure I didn't mis-measure or mis-count.
Good thing I got the 16oz bottle!
From here out I will test at 1:1. I'll post results tomorrow.
I'm sorry about the confusion!

[BigDave]

I don't think you're daft at all. It's on me that I told you to dilute 5:1 and didn't correct that when you received the titrating reagent. I apologize.
The good news is that it appears that a lot of the chlorine demand has been met.
Get a good set of readings for overnight chlorine loss and let's figure out where to go from there.

[mary jo]

BigDave, you are too kind….and most likely a very patient person.

Well, today's results are good and bad I think:
tested last night using 5ml sample. 1 drop = 1ppm

tested @ 11:45pm FC=36 CC=3
tested this morning @ 7:00 FC=35 CC=3

The chlorine loss sounds good, right?
The CC reading of 3 doesn't sound good! (altho I suspect, ahem, it was always testing at around 3 since I failed to multiply the drops added for CC by 6 when I was using a diluted sample…. This one's definitely on me).

So I'm not sure if that changes anything in our approach to getting the pool back in sync.

[BigDave]

Good, keep the shock going. With the 5ml sample test the error is 1ppm so 3ppm is still significant. I don't recall if you have a cover but if you do, leave it open during the day.

[mary jo]

OK- overnight test results are not so good for some reason.
I decided to use the 10ml sample since I now have enough product.
tested last night @ 11:00 FC=35 CC=3

tested this morning @ 7:15 FC=30 CC=3

Is a hiccup like this common? I repeated this morning's test 3 times to be sure.

[CarlD]

Dropping from 33 to 30 overnight? Perfectly normal! when you are super-shocking it's harder to maintain the FC...and you only dropped 9%. I wouldn't worry about that at all.
What I'm wondering is why your CC is so high and not dropping with FC > 30.

PS: I'd run the FAS-DPD test using the 5ml line instead of the ten. If you don't have that line you can either guess where it is or use a kid's med cup that comes with cough medicine with a 5 ml line. Each drop then is 1 full ppm rather than .5. It will take less time to do the test, use half the R-0871, and certainly be accurate enough at those high FC levels.