Ok I'm tryin to prepare for my rez,, so this is what I did. I took a cup of tap water, I turned on my dist 1 conductivity tds meters with automatic temperature compensation HI98300/1/2/3/4 I got a readin of 100.Then I take a cup of my 800 PPM solution put the dist in the solution, it read 70, then I I turned the screw on the side of them meter until it went no higher, I got a readin of 1248. So now I'm confused, so I started over after I put it in the solution. I put the tester back in tha cup of tapwater & got a reading of 170-173 . Then I put the tester back in tha solution & it stayed around the 1248 reading. I turned the screw but nothin happen. Then I read the instructions that the HI98300 is supposed to read 1500 ppm. But it won't go higher tha 1248 in tha solution? Did I do it correctly? Does this sound right?