How to make water? Help please =)

[Simpanra]

Ok, ive made some water =) It looks nice and kind of behaves normally, However, there is one big annoyance that i dont understand. I am trying to make it so that when you enter this map (the water is directly infront of you on a lower level when you spawn) some rocks fall from high above and splash into the water. Only problem is, they do fall, but when they hit the water it acts like glass, they just hit it and stop, sitting perfectly ontop of the water without even making a splash. I am fairly sure i made the water correctly as it works fine when i walk in it and i have a lurker happily swimming around in there. I dont understand what i have done wrong, please reply =)

Cheers,
Edd