I should have known better with a semicolon like you.

One thing that I have never understood that I decided to look up was the use of colon or semicolon. It now makes sense. One is for 2 independent clauses and the other is just to clarify a clause. I should have known better...

http://www.uwsp.edu/english/mbowman/101/Colon_and_semi-colon.htm