Artemia gives out cysts only above 100 ppt & as different salt pans have different salinities, the brine concentration could go from 100 to 330 ppt, when salt crystalizes out & mother liquor is left behind, which is a store house of various chemicals found in seawater.
Regarding collection of cysts from salt pans : Cysts colour is almost the same as that of the salt pan soil & hence not easily distinguishable. Cysts being lighter than brine in which they are found, will get wafted opposite to the direction of wind. Nevertheless, they would be found all along the banks of a brine pond. Skim out the semi-dry & wet top soil of the banks & place in a wide mouthed container containing brine from the same pond. In this way, the cysts will all float on surface , heavier soil will sink in brine & then skim out the floating cysts. The skimmed part will contain various extraneous matter & other floating debris. Remove all of them by passing the whole through a series of suitable filters & you will get pure cysts.
Next, it is essential to very quickly give a bath of distilled water & quickly dry them with blotting paper ( or some other suitable material) & dry the cysts under shade with a slow but steady flow of air. After they are dried, pack them air tight or in Nitrogen. If you do not have time for cleaning etc, you can also keep them in brine collected from the original brine pond - (from where collected.)