I have been using the 10mL testing method with consistent results over time. I decided to use the 25mL sample today as I have been tweaking pump run time and SWG % over the last week to accommodate heavier usage. To my surprise I had to add 32 drops (x.2) using the 25mL method giving me a result of 6.4ppm vs 3.0ppm using the 10mL sample.
I tested again using 25 mL sample and I was at 40 drops with the water still a very faint pink. I verified results with a different DPD test previous owner had left behind, and a test strip. The chlorine is consistent at 3ppm across all tests vs the 6.4-8+ ppm using the 25mL sample. What would cause such significant variations between sample size ?
Here are the rest of my readings:
CC .5 (10mL) & 1+ (25mL)