Hello Headshake,

Yes, it kills the good with the bad. But once it is sterile you can put back whatever you want or need. And JUST what you need.

I think of it like water, go the RO route and strip everything out, then put back what is needed (like cal-mag etc).

One of the things that has helped me is looking at commercial greenhouse growers in my area. (commercial ornemental flower growers for those of you who think I'm refering to commercial mj grow) Their use of, and preperation of growing media, water, nutrients etc. is worth looking at and learning from.

Not only that, greenhouse suppliers are a great source for media and pots.
I get 6" round x 6" tall pots from a wholesaler, cost less then $10 for a sleeve of 125.

BTW: Pro-mix bx is an excellent grow media, comes sterile and is inexpensive.