Pro Mix BX is wonderful. I use that and sunshine 4 mix. I ALWAYS add alot of perlite to help with drainage and to keep the rootzone oxygenated. That stuff has the tendency to get very compacted toward the end of the cycle.
It is PH stabilized so it will want to keep itself around 7 or so. You should ph your feed solution to about 5.5-6 to keep the ph of the soil around 6.5
Also you should really go out and get a ph meter. And if you cant get a meter then get a general hydroponics ph test kit. This way you wont have to post to find out what the ph of your soil is.