The pump gph
should be as close as much as possible with overflow gph
. Otherwise the pump will create noise when choking it so much. A 30 % reduction of capacity is fine but a 60 % reduction is not recommended. in other words a 400 gph
pump when limiting it to 300 gph
is fine. While using a 900 gph
and limiting it to 300 gph
is not recommended. You will surely create noise and vibration.