bizarre..... i downloaded the file from

https://renderfast.com/tutorials/water/#

to check what settings he used in the original thing and everything is the same as mine. so i decided to try and make it within this scene, just next to his and see if mine works here... it id :S. so i thought that meant that something was wrong in my scene. so anyway i went back to my scene and made yet another with the same settings as before and it works :S

wierd eh...
Matt