As wbute advises it is better to have a recovery system where there is a full flow of water.
According to Wikipedia this is a problem."Cavitation is a significant cause of wear in some engineering contexts. Collapsing voids that implode near to a metal surface cause cyclic stress through repeated implosion. This results in surface fatigue of the metal causing a type of wear also called "cavitation". The most common examples of this kind of wear are to pump impellers, and bends where a sudden change in the direction of liquid occurs." It is amazing the amount of wear that can take place in the water necks and pumps due to air bubbles.