bk wrote:

I have a Tetra PF3 filter supplied by a 1100gpm pump. The filter has an
air intake right above the water inlet. This air inlet is very noisy. I
plugged it up yesterday and it great. However this morning the pump flow
seems to have been greatly reduced. As soon as I unplugged the air intake
the flow seemed to be returned.

The only way to really tell is by measuring the output. An air intake will
make the pump _seem_ much faster without necessarily (or even likely)
improving flow.
--
derek