FC levels consistently different

[Whatrymes]

Hey:

I have my new TF-50 kit and have been using it and other methods to act as a surrogate control. I consistently get results that confuse me.

TF-50 FC=3.0
OTO=1.5
Aqua check stick about 1.5-2

I'm real careful with each test and the ratios remain the same?????

Thanks

Oh last TF-50 readings:
FC=3.0
CC=< 0.5
TA=130
pH=7.6
CH=260
CYA=40

... sparklin' and beautiful.

 

[JasonLion]

The FAS-DPD test is much more reliable than the OTO test for determining the precise FC level. Still there is some possibility that you are doing something wrong. It is important to fill the sample tube to the correct level, 10 ml, hold the dropper bottle vertically, to squeeze drops out slowly so they fall naturally and don't get "sprayed" out, and to multiply the number of drops by 0.5 (instead of just taking the number of drops as the FC level).