Lime as a pH up? Lime is best used as a SOIL amendment, and use a proper pH up to fix a troublesome combination of your source water plus ferts. If you want to add calcium, use calmag. Soil pH range is 6.4-6.8 btw. Since most soils will tend to drift lower rather than higher, set your pH to 6.8 to water, unless you observe something else in your own setup.