when to re pot Phal's and is Miracle Gro orchid soil good?

[reor]

snlreor@yahoo.comHi,
I'm new to orchids but acquired 2 plants. So I was going to re pot some and could only find Miracle Gro for orchids in my town so that's what I used. The biggest pot actually had 3 smaller plants in it so about a week ago I re potted them individually. Now that gives me 4 plants. They all seem to be doing good so far. However the one I didn't re pot has a spike growing so I thought I would pull it out and change it's planter medium but noticed it had lots more roots. Should I re pot it into a bigger pot or do they normally have a lot of roots? And is the Miracle Gro good stuff? Thanks