use it, i use it all the time to get great color fades , what it does is shocks the roots, and in return they send out signals to the leaves and tris. if your running a strain that could have purple in it or blue, by using the cold water you get those colors out, and it is a beautiful thing to see, it also is supposed to bring out more tris as well but if the strain has a lot of resin it may help. so get those roots super cold and see what happens