I have done it, and it worked for me, at least in terms of lowering nitrates, with no problems. I have also used sugar for the same effect. Also worked for me, no problems. Dosing too much may give you cloudy water with the bacterial bloom.
It should make your skimmer a little hyperactive.
Vitamin C, as previously mentioned, also helps in this same regard.
Oh and I remember reading that the cheap stuff is better than the expensive stuff. Has the thinking changed on this? Haven't really read up on vodka dosing in a while.