im using it at 10ml/gallon of 5.8 ph'd water in a spray jug. then put about 1 liter(per 5 gal bucket)over the hydroton and drench for 24 hrs, flush and repeat every other day. dont spray once and think you got em, the eggs will make it through if you dont keep up the every other/third day drench. make sure to wear gloves, that shit is bad news if you ingest it (have it on your hands, then break up a bowl and smoke it.........) so be careful with it and if you spray it in a mist shut down all fans. im kinda crazy about not getting it on me so i went to harbor freight and bought a rain coat and rubber gloves for when i spray. i even wear a full face 3m respirator with organic filters. and if you have overspray on the plastic sheet(mylar or panda film, be sure not to rub against the wall as the residue from your spray will be on there, i like to clean with a rag between grows just to disinfect too.