Did you try to Manually add more water in the filter, untill the flow is
smooth?

"Shassmom3" wrote in message
.. .

I have a 120 gallon tank with two built in overflows. One side seems to
work fine and the other side makes a flushing sound. The water level in
that column drains down and then fills back up. Is there anything I can
do to fix this problem?




--
Shassmom3