2, don't put it under the god of wealth, because the Feng Shui ball has water. If you violate the taboo of "going into the water" in Feng Shui, you are in danger of breaking the money.
3, don't put it behind the sofa, because from the perspective of geomantic omen, water is impermanent, and it is difficult to be stable with its backing, so it will be very reliable without mountains, which will affect the stability of house transportation. But if it's next to the sofa, it doesn't hinder residential feng shui.