I was checking my pool with my test kit and when I got to the CH test, I added the water to the bottle and when directed to put the 5 drops of the I believe the forst was titrant, the water should have changed to red. It did not change to red after the 5th drop, so I put it a sixth drop and it di turn a little red. I then continued the test and added the other drops of the second bottle and counted the drops till it turned from red to blue. By adding the 6th drop, would that effedct my reading? I dont know why it didnt change color after the 5thdrop. I used the test last year and it worked on the 5th drop. maybe the liquid drops lose potency from season to season. this was a bottle i had purchased last year. But like i said it worked last year after 5 drops but this year i needed to add a 6th drop. let me know. thanks.