Replying to REAL techi question see if i can help

mad props if u can figure this out:

aight so i have 2 rails with composite decking, one type has decking with a fairly rough grain to it and long lines running the length of it, the other is perectly smooth with no grains and no surface lines
PROLBEM: -the box WITH a grain and lines slides well and need only a little water now and then
- the SMOOTH surface does not slide well at all and needs to be watered constantly

I thought i would have the opposite problem, what is going on? why? how can i fix it? thanks and props if u figure this one out