Microbubbles from pumps

[Cory]

What is happening when an external pump shoots out microbubbles when it gets plugged?

 

[Randy Holmes-Farley Verified Community Expert]

Probably cavitation, where the pump is spinning round and round in the same fluid. Localized vacuum behind the impeller blade leads to gas coming out of solution into gas phase (filling the vacuum).

 

[Cory]

Probably cavitation, where the pump is spinning round and round in the same fluid. Localized vacuum behind the impeller blade leads to gas coming out of solution into gas phase (filling the vacuum).

Do you think this could cause oxygen to come out of solution?

 

[Randy Holmes-Farley Verified Community Expert]

Do you think this could cause oxygen to come out of solution?

O2 and N2 (and other gases, but they are very minor components) both come out during cavitation to make fine bubbles.

 

[Cory]

O2 and N2 (and other gases, but they are very minor components) both come out during cavitation to make fine bubbles.

Ah okay. Ive noticed when my pump cavitates the next morning my fish are breathing fast. Potential oxygen deprivation? No skimmer in this system or overflow.

 

[Randy Holmes-Farley Verified Community Expert]

Ah okay. Ive noticed when my pump cavitates the next morning my fish are breathing fast. Potential oxygen deprivation? No skimmer in this system or overflow.

Might be. Whether that is related to the cavitation or not I do not know. Cavitation works best to reduce the gas in water that is supersaturated, but it may also be able to drive it down if the bubbles leave the water before redissolving.