I have a hard time comparing the shades for the ph and chlorine on the basic test kit and find myself using the FAS/DPD test to really know where my chlorine level is at. I decided to try the WaterGuru. Using the K-1000 I thought I was at 6 ppm and 7.4 for PH. I then tested using the FAS-DPD test and the result was 5 ppm. Testing with the WaterGuru, my results were 3.6 ppm and PH of 7.7. After one test I’m ok with the results. This is my first pool and it’s saltwater. I have had crazy swings trying to dial in the SWG so hopefully this helps.