Do you have sludge accumulation data?
Fuji Clean USA requires that sludge be measured at each 6-month service visit. As directed in the Fuji Clean O&M Manual, system pumpout should occur when sludge levels reach 35" in the sedimentation chamber (first chamber) or 16" in the anaerobic chamber (middle chamber). Based on "normal" full time household water use, Fuji Clean estimates that a pumpout should be required about once every 2+years. A higher pumout frequency will be required with high hydraulic or organic strength influent – particularly if a garbage disposal is being used.