Clear, but no chlorine???

[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.

[BigDave]

I pretty much agree with CarlD, the FC loss is not such a big deal but the CC consistent at 3ppm.
Two questions:
How much bleach did you use yesterday?
Is there any chance that a bromine product has been put in the pool.

[mary jo]

OK- it was actually a 5ppm drop (35 down to 30). Did I wait too long to take the morning test? (should I test before sunrise ~ 6:00?) Yesterday is was overcast and rainy all day. This morning it's sunny.

I added 1 1/2 jugs yesterday. Yesterday morning's initial reading was 35 so I didn't need to add much to keep it at 30. I added the last jug @ 9:00 and tested at 11:00 and got 35.

Not sure what bromine is, but the only chemicals ever put into my pool this season: pH up (about 15 lbs), phos-free (1.4L) and 3" chlorine tablets for the inline chlorinator.