This is a 3 shot bracketed exposure combined in photomatix pro.
Later on in the evening I removed the 0.9 ND filter and replaced the hard edge 0.9 ND Grad with the soft edge version and shot a faster exposure. This was to try to capture more motion and texture in the water instead of such a soft milky feel. although the was less light as the sun fell lower, removing the main 3 stop filter alowed the rocks to be more illuminated, quite a different feel to this image
Sigma 10-20mm Lens @ 10m
0.8 sec Exp
Hitech 0.9 ND Grad soft edge