In veg, I start with a 5 gal bucket of water and I add about 3ml/gal, to my RO water. That brings the PPM to just over 200. Then I'm adding 6ml/gal Rock GROW, and 4ml/gal Rock SuperCharge. This is according to the nutrient chart. The ONLY other thing I'm doing is making beneficial tea, once a week.
A cal / mag additive is optional. Personally, I would use it even with the well water.
60cal, that's a great question. It is best to have plenty of run off. If you only feed until you see a TINY bit of run off, there is a chance the PPM or PH could fluctuate inside the media (rockwool). The more you run off, the more confident you can be that the PH and PPM in the root zone is the same as what you're pouring in. And this is why, in flower, we irrigate (recirculating) for a solid 15 minutes at a time. I've actually seen minor deficiencies in veg, when I don't water enough. I used to recirculate in veg too, but I find I enjoy hand watering them.
