Hey
I've never needed to use the stuff myself, but I've only heard good things about it, from many sources. It had better work for that price!
As for the cloudiness, it's possilbe that the biospira has taken effect, but there wasn't enough of it so you may be having a bit of a bacterial bloom. nothing to worry about by any stretch, it should clear up between a couple of days to a couple of weeks if you don't do anything drastic to the aquarium.