Hey all, had a heavy bather load over the past week or so and neglected testing. Checked after they all left and FC is 0 so I threw all the chlorine I had leftover into the pool and cranked up the SWCG. Don’t think I have a problem now, but wanted to do the OCLT to be sure.
First reading was 21 drops (FC = 10.5), and CC <= 0.5
Then, for the heck of it, I thought I’d try again, and got 22 drops. Finally, I tried a 3rd time and got 23 drops- so in 3 back-to-back FC tests I had a range of of 1.5 PPM between the results. This seems greater than I would have expected. I should mention that I am by nature very precise- I use a syringe to make sure my vial (which has been thoroughly rinsed and dried) has exactly 10 ml of pool water, and when I drop the R-0871 I brace my hand to avoid jiggling and do so slowly and methodically. So the difference certainly isn’t through carelessness in my performance of the test. Could it be the amount of DPD powder I use? Or the fact that it has crystal chunks in it? The instructions say the exact amount doesn’t matter but to use a heaping scoop. All I can think is that the variability is with that. Could it be?
Secondly and largely unrelated to the previous question, why is the instructions for adding R-009 (TA test) in the TF-100 kit the only one that explicitly says to wipe the tip of the bottle after every drop? Seems you’d want to be consistent between all droppers, no?
First reading was 21 drops (FC = 10.5), and CC <= 0.5
Then, for the heck of it, I thought I’d try again, and got 22 drops. Finally, I tried a 3rd time and got 23 drops- so in 3 back-to-back FC tests I had a range of of 1.5 PPM between the results. This seems greater than I would have expected. I should mention that I am by nature very precise- I use a syringe to make sure my vial (which has been thoroughly rinsed and dried) has exactly 10 ml of pool water, and when I drop the R-0871 I brace my hand to avoid jiggling and do so slowly and methodically. So the difference certainly isn’t through carelessness in my performance of the test. Could it be the amount of DPD powder I use? Or the fact that it has crystal chunks in it? The instructions say the exact amount doesn’t matter but to use a heaping scoop. All I can think is that the variability is with that. Could it be?
Secondly and largely unrelated to the previous question, why is the instructions for adding R-009 (TA test) in the TF-100 kit the only one that explicitly says to wipe the tip of the bottle after every drop? Seems you’d want to be consistent between all droppers, no?
