replacing PS capacitor

Thanks for the replies guys
I think I will stick with 6800µf
At first I wanted to put 22000µf cause i thought I would lower ESR
and the 22000µf Thel elkos are about the same dimensions to the original 6800µf in my amp.
But since I have just purchase RIFA 6800µf with quite low ESR, I think i will do with the safe replacement. Thank You