Contains this paragraph about 2/3rds into it.
Another source of Ca ions is the well water used for irrigation. In Florida, well water comes from the Floridan aquifer which is located in the limestone rock underlying most of Florida. Water pumped from this aquifer will contain significant concentrations of Ca, often on the order of 100 parts per million. This concentration is similar to concentrations of Ca in many recommended hydroponic nutrient solutions. Low-Ca irrigation water would be rare in peninsular Florida.