I have a fluval 304 in my 55 gal
Last Friday I bought some cardinal tetras (on sale at $1.88 each).
The problem is that they are too small for the output that the 304 puts out. They ended up getting stuck in a current in one of the corners and having to fight it non stop.
The only thing that I have found to alleviate this is to aim the nozzle at the nearest side and close the exit valve about 50%. This still provides plenty of surface movement without and currents that overpower the fish.
My question is will this hurt my filter? I really don't have any alternatives other than buying a new one (which I don't want to do), but I don't want my existing one to get damaged either.