We tried the gradient density centrifuge method which can be found here: http://www.in-gender.com/CS/forums/thread/34880.aspx
None of the sperm survived the 20min spin. However, we realized after the fact that the test tube was improperly placed and was rubbing on the cover. So it's possible the friction created too much heat and killed them.
On a side note, I've discovered my ph is a 9 and dh's is a 7