Step sludge and residue with a sludge judge to verify pumping need

https://wiki-burner.win/index.php/Hydro-Jetting_vs_Standard_Sewage-disposal_Tank_Cleaning:_When_and_also_Why_to_Make_use_of_Each

Step sludge and residue with a sludge judge to confirm pumping requirement, then blend contents carefully to suspend solids so the vacuum truck gets rid of both layers, avoiding blockages and premature refilling.