A TA of 900 meant you had to put 90 drops of the R-0009 in to get the sample to go from green to red. Are you sure that's what you did?

Review of TA test
1) Fill tube to 25ml mark
2) Add 2 drops of R-0007 and swirl
3) Add 5 drops of R-0008 and swirl--sample should turn green.
4) Add 1 drop of R-0009 and swirl
5) Repeat #4, counting drops, until sample turns red and stays red.
6) Multiply # of drops added by 10--that is your TA number.

CH:
1) Fill tube to 25ml mark
2) Add 20 drops of R-0010, and swirl
3) Add 5 drops of R-0011, and swirl. Sample should turn red or pinkish red.
4) Add 1 drop of R-0012 and swirl
5) Repeat #4, counting drops, until sample turns blue.
6) Multiply # of drops added by 10--that is your CH number.

Hope this helps.