Throughout pumping, maintain consistent vacuum, avoid tank wall damage, separate heavy solids with agitation
https://station-wiki.win/index.php/Sewage-disposal_Tank_Pumping_and_Servicing:_A_Property_owner%27s_Step-by-Step_Quick_guide
Throughout pumping, maintain steady vacuum, avoid tank wall damage, separate heavy solids with agitation, and never ever go into the tank; deadly gases require rigorous confined-space safety procedures.