Throughout pumping, maintain stable vacuum, avoid tank wall damage, separate heavy solids with agitation
https://wiki-tonic.win/index.php/Septic_System_Pumping_and_Installation:_Cost-efficient_Solutions_You_Can_Trust
During pumping, maintain constant vacuum, avoid tank wall damage, separate heavy solids with agitation, and never ever go into the tank; deadly gases require stringent confined-space safety procedures.