i've been using the earth juice 3 part formula since i started growing last year. it works great, but i've had problems reading the ppm since i got my meter. my read outs are very low. my tap water reads out at about 250, after adding the ej in the normal dose it's only like 550. today i checked the ppm of the extra strong mix i made and it was only 1000 after adjusting the ph(should've checked before adjusting, but didn't think to). just wondering if anyone has an explanation for this. the ph meter has been calibrated.