Always, always pH your water. Doing so will prevent the mass majority of cannabis growing issues.
It is widely known that in soil, a pH of about 6.2-6.8 works best (I personally do 6.4-6.5), and in hydroponics, (correct me if I'm wrong), 5.5-6.2.
If you need to pH down, use pure citrus (lemon or lime) juice (vinegar also works well, particularly cider vinegar), and for pH up, baking soda works wonders.
-spek
It is widely known that in soil, a pH of about 6.2-6.8 works best (I personally do 6.4-6.5), and in hydroponics, (correct me if I'm wrong), 5.5-6.2.
If you need to pH down, use pure citrus (lemon or lime) juice (vinegar also works well, particularly cider vinegar), and for pH up, baking soda works wonders.
-spek