This will be the best bang for your buck mine is going on 3 years calibrated every year and it’s dead on point! https://www.amazon.com/Hanna-GroLine-Waterproof-Hydroponic-HI98118/dp/B09CC1PMTV/ref=mp_s_a_1_5?adgrpid=76064307294&gclid=Cj0KCQjwuuKXBhCRARIsAC-gM0iDJlaXY9ItEVdAmSHA8rkXtbMbKoj2HU7y9x8CQ0iNZRg3_m6syaYaAhYuEALw_wcB&hvadid=378379241215&...