[gregebowman]

Check your maintenace costs also. Sometimes I get so involved in building up fleets of ships, I forget that all of those ships costs so much a turn to maintain them. So if I see I'm going into a negative balance, I research the next level of extraction for mineral, organics or "radios", and then start colonizing planets with the needed m, o or r's that I need to stay ahead of my costs. Eventually, as you expand and colonize more planets, you'll get more than you need, and then you'll need more storage facilities.