I would use a fast draining potting soil, such as cactus mix, though African violet mix would do in a pinch. Allow the top 1/2 inch of soil to dry between soakings. If your tap water is hard and/or salty, the best means of watering is to drench the soil from the top down, and let it drain thoroughly before returning the pot to its tray. If your water is fairly pure, or you have a good source of reverse osmosis water, watering from the bottom up works the best. Frequent, light feeding, with a 3-1-2 proportioned formula works the best in my experience.