During pumping, maintain constant vacuum, avoid tank wall damage, break up heavy solids with agitation

https://wiki-canyon.win/index.php/Sewage-disposal_Tank_Pumping_and_Maintenance:_An_Individual%27s_Step-by-Step_Manual

Throughout pumping, maintain consistent vacuum, avoid tank wall damage, separate heavy solids with agitation, and never get in the tank; lethal gases require stringent confined-space safety procedures.