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Show 95 Great Salt Lake. Physical factors limiting salt production are: ( 1) weather, ( 2) quality of brines, and ( 3) plant capacity and pond area. Weather conditions, which are not controllable or closely predictable, directly influence the rate of solar evaporation. Years of low precipitation favor the salt industry because the Lake level falls, causing the brines to become concentrated and reducing the area necessary for evaporation ponds. Warm springtime temperatures that cause rapid melting of the snowpack cause short- term dilution of the brines at the start of the pond- filling season. The ideal weather for evaporation is warmer- than- average temperatures between May and October, moderate winds, little cloud cover, low relative humidity, and low precipitation. Cool nights favor formation of coarse salt. Usual variations in evaporating conditions have less than 25 percent effect on salt production. In general, the areas around Great Salt Lake have good climatic conditions for evaporation. The quality of brines for salt production consists of two factors: ( 1) their composition, and ( 2) their overall concentration. The removal of sodium chloride by precipitation in the North Arm leaves magnesium, potassium, and sulfate in the brines, increasing the bitterns that must be washed from the ponds. The most serious effect of increased bitterns, ( particularly magnesium) on common salt production is that the concentration of salts required to precipitate the salt in the harvest ponds increases. Frank Calladay of Morton Salt reports that prior to the precipitation of salt in the North Arm of the Lake, halite precipitated in ponds when the specific gravity of the brines was 26.5* Baume ( Sp. Gr. = 1.223). At present, precipitation does not occur until the gravity reaches 27" Baume ( Sp. Gr. = |