with a bl touch it is easy to adjust the height.
Try it out to in- or decrease the height wihle printing and see what habben.

If its to close you get a rough surface, because there ist to much material for to less space between nozzle and bed.

If its to far, the lines do not connect to each other.

In the perfect height you get a clean even first layer.

I'm using the official BLTouch kit from Creality. 

Others pointed out that it may be too close so I adjusted the Z-offset a tiny amount.

it seems your nozzle is too far from the bed.
You have to level your bed.
I recommend a BLTouch or a clone for the leveling.
I use a clone and it works perfectly.

Anyone knows what could be causing this?