I just use plain water pH 5.5 to 6.5. I keep the bottom inch immersed for two days, then I pour the water out and give it a day to dry, then I repeat until I see roots, 2 days wet, 1 day dry. Controlled dry spells cause the plant to invest energy in root development. Just cloned 38 white widows and had 100% of them root. During the wet days I also spray the plants and the walls of my humidity dome with water and keep the dome vents closed. During dry days I open them up.