What I like to do with amazon since people like to be all over with reviews is go straight to the manufacturer website and look at reviews there. I bought a tds meter off amazon, probably the exact same one and mine works great. No fluid with it tho but it measures 0 on distilled water and is pretty solid on the readings as I add stuff. Ive only used it once though since I dont have a solid understanding of it and Im not running coco or hydroYeah, I noticed in my Amazon search that there was a meter to go with the fluid. So I thought I would buy this one also, but when I looked at the reviews ... it was saying it was a knock off and now I don't know which one to get.