We're plastering our walls in the livingroom with a mix of 1 part colored lime putty to 1 1/2 parts sand (the sand we are using is Kwikcrete Play Sand and has been screened so the granules are less than .5mm). This is the 3rd coat over blue board. But upon drying, parts of the wall are coarser than other parts, which would be okay, except the color is much darker in these areas, giving an unattractive and unwanted streakiness. Any guidance to why this is happening and how to solve it would be greatly appreciated.

Harvey