I've had issues with perlite.....BAD ISSUES. I asked my hydro guy if I needed perlite for this soil and he said no so I'm not doing it. He said you CAN use it but with this particular soil (Fox Farm Ocean Forest) I don't need to have it. I may try some on my NEXT soil grow though because it does seem to require less watering than I am used to in my many years of soil experience.