Due to their gravitational pull, these gas giants are often orbited by many moons, sometimes the size of small planets. Not surprisingly, these moons are home to many profitable gas and chemical gathering colonies. The only needs these colonies have are food and a little energy; they produce their own water, which can be extracted from the chemical mixture that makes up the giant's atmosphere, so they do not depend on it's import.
Worker increase per cycle (3 hours) is a random value between 1.2% and 2.4% plus above-mentioned bonuses when upkeep is met.
If upkeep is not met workers leave.
When population is over 100,000, an overcrowding-effect takes place and growth will slow down with increasing population. For very big planets and starbases there may happen a worker-decrease, even if all upkeep is provided.