It is the name of a prominent Christian saint, Saint Jerome, the translator of the Vulgate.Jerome ranked among the top 200 names given to boys born in the United States between 1903 and 1985. It has since declined in popularity and was ranked as the 616th most popular name for American boys born in 2008.t is the name of a prominent Christian saint, Saint Jerome, the translator of the Vulgate.
Expected Levels. Total hardness in freshwater is usually in the range of 15 to 375 mg/L as CaCO3. Calcium. hardness in freshwater is in the range of 10 to 250 mg/L, often double that of magnesium. hardness (5 to 125 mg/L). Typical seawater has calcium hardness of 1000 mg/L, magnesium.
UNDERSTANDING CALCIUM HARDNESS. Calcium hardness must be actively managedâalong with pH and total alkalinityâto keep water in proper chemical balance. Current industry standards call for maintaining calcium hardness in the ideal range of 200â400 ppm in pools and 150â250 ppm in spas. The Role of Calcium Hardness in Water Balance. While hardness in water consists of both calcium and magnesium salts (total hardness), only the calcium component is relevant in the water balance calculation for pools and spas.