question about pre-emergene to my south east landscaping associates.

what your preferred chemical to spread for weed pre emergent. i use pendimenthalin (.086) as my first application then prodiamine (.36) for my second app. i have a buddy that uses prodiamine for both his applications. then have another friend who uses cavalcade for both of his and his applications are at completely different times then mine. your thoughts?

 

*****meant question about pre-emergent