Hey my local grow shop tried to tell me any sensor to check the pH balance of water was like 200+ bucks. What? I looked online and found this one: PH/Ion Pocket Testers And Oakton Waterproof EcoTestr PH 2 Pocket PH Tester - Cole-Parmer Catalog It's only $75. So I don't know what that lady at the store was talking about. I'm going to order this one. Can anyone vouch for another, similarly priced one?