For an even longer exposure during day time I recommend using an ND filter, or simply a welding glass in front of the lens.
Definitely ND filters will give an advantage. Taking your shutter speed way down will make an action of a water smoothen more BUT will make it brighten the image more. Having ND filter will compensate on the exposure given by the longer shutter speed that an aperture can't compensate.
Good find, Bex. I generally don’t like the candy floss effect from a long shutter speed for moving water but this close up is rather different. I am usually looking for a faster shutter speed to eliminate movement in flowers and insects when taking close ups. Must look that filter holder out.
I don't if it features in a landscape scene, but I've seen a few close ups and I think it works well. The author of the thread was a really talented photographer. It was pavel or something, I'm not sure. I think they're still around.
Couple of things can help -
Shooting with a tripod
Longer shutter speeds