68, im being told i should leave my parts in the copy cad for at least 20 min. before i drop them into green drab chromate

Hummm, my parts are coming out excellant out of the copy cad solution, its the green drab solution i cannot figure out>>

Why or should it not be green in color instaed of yellow?? Most of my green grab parts are smaller than your little finger, why must i put them into a cad solution for 20 min.?? Got me confused??