Welcome To Whitehall Township Whitehall Township is located in the center of the Lehigh Valley. The Township is one hour north of Philadelphia and an hour and half from New York City.
SALINITY OVERVIEW Salinity is the concentration of dissolved salts in water, usually expressed in parts per thousand (ppt). Objects float higher in salt water than fresh water because salt water is denser (heavier per unit of volume).
What does the term Parts Per Million (PPM) mean? Total dissolved solids (TDS) is typically expressed in parts per million (ppm). PPM is a common unit for measuring the concentration of elements in the nutrient solution. One ppm is one part by weight of the mineral in one million parts of solution.