Depends on the size of the pump. One big pump can run 4 bubble wands, but the smaller $10 ones can only run 1 or 2. My air pump has 4 outlets (about $40).

The jet spa is not for looks. The picture is of my bubble cloner, not my resevior which has a pump that not only sprays air bubbles into the nutes, but circulates the nutes as well. I forget what that pump is called but it has a directional head, and you can choose to have air bubbles with the circulation or not.

The same pump I use for my cloner I use one each in my flower section and veg section. There are 8 individual small reseviors for 8 plants in each section. I make the four outlets into 8, and run 8 small air wands (16 total for 2 pumps), and I get plenty of bubbles in each resevior.