Procedure sludge and scum with a sludge judge to verify pumping need
https://wiki-tonic.win/index.php/Reputable_Sewage-disposal_Tank_Emptying_and_Setup:_Smart,_Cost-Saving_Techniques
Step sludge and scum with a sludge judge to verify pumping need, then blend contents carefully to suspend solids so the vacuum truck eliminates both layers, preventing clogs and premature refilling.