As was stated: Tap water is all that is needed. Make sure the water is 69-71 for optimal rooting.(I use a small chiller year round) I also like to put an additional air stone in the rez. This is all that is needed. I don't add any rapid rooter until roots have sprung.....Once they have popped than just a little Rapid Rooter and that it. ^This is proven and works. Having said all this i have just run into a strain that won't budge(Dutch Passion-Euforia)- Its blowing my mind. No comprendo. Everything roots with ^^^.