Koi Forum • difference in water level in nexus 210 filter : Koi Talk

hi I am new to the forum so I’m not sure if I am posting this on the correct page , but here goes .Could anyone tell me what the water level difference should be on a nexus 210 between the inner and the outer compartments . Pond size 2650 gallons gravity fed thro 4in” pipe straight into 210 full capacity 0f k1 in the filter, super fish 8ooo pump, blagdon 65 air pump .I clean the filter twice a week. Current water level difference with pump running is 2 1/2″ inches. is this the norm. Any help would be gratefully received .