For starters, I can't review this from the perspective of someone who needs a salt reader. I don't have a saltwater aquarium, and I'm not planning on using my softened water for my freshwater aquarium. However, I did include a picture of the product's included salinity chart.For my testing of this meter I used settled well water. By that I mean water straight from the bypass valve into a 5 gallon bucket that's sat untouched for a few days so that most of the sediment is on the bottom. I wanted to test it like this because this is how I plan to remineralize RO water (by mixing it with settled well water) for my freshwater aquarium tanks. I already knew from previous testing with strips & droppers that I have very high pH and very hard water; these readings go off the chart on those strip & dropper tests.Right off the bat this product was confusing to calibrate. I can tell they tried to make the instructions clear, but some details were left out that frustrated me. They say to calibrate using the liquid solutions included in the kit, and to wait until the reading is stable to push the calibration button, but did that mean I should wait for ANY stable reading, or for the reader to say the exact bottle numbers before I pressed the button? I waited a long time watching the pH numbers creep up...the first one got there eventually, but the second one refused to budge above 9.9 and kept timing out. Eventually I got sick of it and just pressed the calibration button at 9.9, which immediately caused it to turn to 10. This leads me to believe that the instructions weren't clear, and that ANY stable number is fine because the calibration button changes it anyways. This wasn't an awesome experience considering you're supposed to re-calibrate meters like this frequently. You also have to read the fine print on how long the calibration fluids are good once opened.After calibration I used the meter to test the settled well water. It is a live reading so if you pull it out of the water, the reading immediately changes, so you have to follow the instructions to "hold" the reading on the screen before you remove the meter from the water. That was easy enough to figure out. I got readings of 8.2pH and 8.3pH.The salt & TDS readings were the same at 404ppm, which confused me. I compared them to my separate TDS meter, and everything was off. My other TDS meter has a 700ppm scale that's recommended for well water and a 500ppm scale that's recommended for other things, and this meter's 404ppm didn't match either one of them. Also, the instructions didn't even say which scale it's reading in, essentially making the TDS function of this reader a total bust for me. Since I don't need the salt reading and I can't trust the TDS reading, this product is ONLY a pH reader for me.Don't get me wrong, I am grateful to FINALLY have a more reliable pH test, because the strips & droppers are really only suitable for the 6-7 range. I need to know a more exact higher pH reading because I am aiming for an 8.0 max pH in my RO/well mixture. That 0.2-.03 difference matters to me, so this product is superior to what I've been using before this. However, I don't have any other pH meter to compare it to. Plus, I don't need a salt reading. For those reasons I don't think it would be fair to give this product less than 4 stars, but I did seriously consider giving it 3 stars due to the unclear calibration instructions and the unclear TDS ppm scale.