Big Lou, the line recomended by J.C. is a great line and will get your fly down fairly deep, however to get down realy deep try a shooting head attached to some super braid as your running line. the braid will not slow down the sinkrate of your shooting head at all and will not be nearly as affected by the current due to its being very thin.
A word of warning though, you will have to be very carefull not to get tangles in the braid and if you do hook a big fish while the braid is tangled round your hand there will be some serious cuts to sort out. A glove is a must! If this doesn't appeal then simply use amnesia or something similar.
All the best.
Mike.