In the water
and to answer when...when your PH is too high or too low.
Do you have a PH tester?if not go get one NOW!
For soil it should be 6.8-7.0
For hydro it should be a litlle lower ,I think around 6.0
To figure out how much to use expirament...start with a tiny dose and test then go from ther.
:rasta: