Tomato soil should be fine. Very dark soil sounds good too. Let me know how your pH test comes out. If you decide to pH test your water as well, be sure to meter the runoff water as well as the water going in. In other words, get some of the water that comes out of the bottom of the pot as you water, and test that. Also feel free to post a few pix of the plants as they develop.

There are a lot of smart people on this site who would be happy to help you out. More info will get you very good answers. Good luck, and show your plants you love them:-)

Dboy