Longtime lurker... Just got my TF-100...
My understanding is that the ph test become inaccurate at about 10 ppm FC.
After some practice with the CYA test it looks like I'm at 60 (thanks to the PS suggesting I add CYA... Lesson learned...).
Anyway with a target of 9 PPM FC, it seems I'm on the cusp.
I'm wondering what people who have very high CYA (target FC > 10) do to test ph?
And what Are the symptoms?
I'm at 12 FC now, and the ph test looks to be about 7.4.
Thanks in advance!