Aqua-Computer Aquacover Dual DDC Top

this what is for?"pump top" what means?

felix thanks(mi mou ta steiloune se deka xronia fovame mono,eidikotita ksekinao aygousto,stratiotikos giatros eimai,to pump top ksereis ti kanei?)

melle if we had a biger reservoir we d had problems with space?