Question: what to do after you beat crasher wake in pokemon diamond?
Answer: There should be a team Galactic member next to the Pastoria Great Marsh. ... 
I agree. ... 
After you have defeted the pastoria gym leader there are are a few things to do. ... 
the next gym leader is in Canalave City After Hearthome,then u go back to Pastoria and go to Sunny Shore City.