Measure sludge and residue with a sludge judge to verify pumping requirement

https://kilo-wiki.win/index.php/Sewage-disposal_Tank_Emptying_Schedule_as_well_as_Ideal_Practices_for_Long-Term_System_Wellness

Step sludge and scum with a sludge judge to verify pumping need, then mix contents carefully to suspend solids so the vacuum truck eliminates both layers, avoiding clogs and early refilling.