Keep getting the yellow shit ph meter's from ebay or wherever. Sometimes they last and sometimes they don't. Seems like the ones I got recently don't last at all and never worked from the beginning. Give me a ebay seller that sells the cheap yellow ones that are $10 or a more expensive one that will last for hopefully a year. I like the ones that calibrate by turning the screw.....FUCK THIS SHIT, I'M SICK OF GROWING THIS BS.