Problem - render water with v-ray

ludopoot

Hello,

I've tried to make realistic water, I did evrytig what fernamdo did in this video that I found here:
http://www.youtube.com/watch?v=8D_3bPg_62w&feature=youtu.be

But someting went wrong... You can see below my render isn't the same as fernando's.
If you spot the problem please let me know.

Ithink someting is wrong with the opasity of the material, but were to change that?, in the material previeuw the material looks perfect...

Thank you in advance !!

andybot