The best sources of sodium chloride are “plain” or non-iodized (Kalibrate already contains the proper amount of iodide so additional iodide which would be contributed by iodized salt is not necessary), greater than 99% purity, and do not contain anti-caking agents such as Yellow Prussiate of Soda (a.k.a. “YPS”), stabilizers such as Sodium Cyanurate, buffers, or metal detoxifiers; so-called “standard pool salts” with no additives may meet these requirements and can often be purchased in 40-lb. bags for pennies per pound. Keep in mind that FCC- or Food-grade salts will have a lower percentage of insoluble materials and elements such as calcium and magnesium per unit mass than will pool salts; USP- and ACS-grade salts are even better. For specific recommendations of sodium chloride, contact us directly.