Landscape painting

I have setup a landscape material, but my landscape goes checkered once I get to the 5th texture. I was told the max texture limit per component was 16? I am only using 8 until it blanks out.

Screen capture - 3c6acaadc06a2612c00e1521bfee4652 - Gyazo (when I start painting 5th it checkers)

Does anyone know how to fix this?