I tried testing the TA in my spa using the Taylor K-2006. I added 2 drops of R-0007 with no color change. But when I added 5 drops of R-0008, it turned red instead of green. When I tested my pH, it was extremely low (don't know if that info helps). What gives? These past two days there were 2 bathers using the spa separately for 30 minutes at a time.
260 gal., outdoor, bromine, cylinder filter