wrote

Go to your local central vac dealer/service place and see if they
have anyhoses that got too short for the original user due to the ends
breaking off too many times and scrounge some - or buy new central vac
hose. It's not 2.5" but that just means you will get higher velocity
for the same flow.

Anything smaller than 2.5" is too small for the pecans to go through without
clogging up a lot.

Steve