Hello; I like to use one with two output nipples. I run tubing from each nipple to fed into a common set of gang valves and then to the various air accessories. This way if one of the rubber (may not be rubber in some pumps) pump parts and small valves on one side the other side is likely to still be ok and still pumping. There will be a reduction of bubbles but not a complete loss of bubbles.
This may no longer be necessary, but I try to hang air pumps above the water level of my tanks. There use to be a danger of water being siphoned out of a tank thru the air tubing during a power outage or pump failure. There are one way check valves that can be added to the air tubing as well. Hanging also helps reduce the vibration transmitted from the pump and helps to make things quieter.
This may no longer be necessary, but I try to hang air pumps above the water level of my tanks. There use to be a danger of water being siphoned out of a tank thru the air tubing during a power outage or pump failure. There are one way check valves that can be added to the air tubing as well. Hanging also helps reduce the vibration transmitted from the pump and helps to make things quieter.