the meter was calibrated at 7 and 10 (the meter shows what buffer to use it was set to 7.01 10.01 and 4.01) I just ordered a new batch of buffers and try again. Could the phenol red that I got last year is bad?

Carl,
was my understanding correct that you can not trust the ph reading above 3 ppm ? is this true of last year PS233 and this year refill of phenol red?
Amir