So I kept killing my bonsai and I think it was getting too much of tap water... When I took the advice of watering with filtered water it helped with the health of my bonsai. This meter has kept me on track with caring for the two I have now and have managed to keep living. I love this meter as well as the other I have for light and moisture, not I can keep my plants alive and I do not have to guess and waste money. This has ensured me a great green thumb.