ok, i just picked one of this meters up from the store. When i turned it on it started to jump all sorts of numbers?? i though i didn't have to calibrate this right away. did i get a busted meter?? i got it for mixing my nute solution for my soil grow. after i got my nute solution mixed it keeping reading 5.5 but slowely going down, edoes anyone have any experince with this meter that coulkd help me out?? i have never used one of these meters before. it was pricey