Testing chlorine with Taylor K-2006 kit?

[AndieP]

I noticed that you can test at the 10ml at 0.5 per drop or the 25 ml at 0.2 per drop. Is there any reason to use one vs the other. With high chlorine levels I was using the 10ml just b/c it took less reagent to get a reading but this morning I tested twice and got 2 different readings. With the 10ml sample I got 11.5 and with the 25ml I got 9.5. What would cause such different readings? Which one is more likely to be right?

Thanks!

[Poconos]

When in doubt, do an experiment. I have a K-2006 too. Only difference I used a 10cc syringe to set the sample volume. With the 10cc sample I got 5.5 (11 drops), 25cc was 5.6 (28 drops). I would tend to believe the 25cc measurement because the sensitivity per drop is lower and the volume measurement is more accurate. Using the syringe both the 10 and 25cc levels in the test vial showed slightly above the marks on the vial. Nothing of significance.
Al

[waterbear]

Al is right. The 25 cc measurement produces a more precise measurement....but probably is not necessary for normal tesing....It's a swimming pool, not rocket science! Your difference is 2 ppm and that is not going to make a lot of difference in your pool at chlorine levels that high. It's still a lot more precise than you would get with a DPD or OTO test, both of which would need dilution to get readings that high with available test kits!

[AndieP]

Thanks Al and waterbear. I am still in the conversion process so I was trying to keep the chlorine at shock level, which with 0 CYA is 10ppm. And these were first thing this morning readings so it seems my chlorine held pretty well overnight.

I did measure with a syringe and both 10 and 25 were slightly above the mark on the tester.