Pull harder? Twist as u pull?

Use a tiny flathead screwdriver to pry the rubber hose off of the tube. Stick it in between the tube and the hose. Then keep workin your way around as u spray some soapy water over it. Hose should break loose and slide off.

 

I usually grab them with small channel locks to get it to spin initially.

Worst case scenario you cut a slit in it with a knife and buy a new one.