Bulk starter

Bulk starter

Hi guys

im New to sourdough  although I can maintain my starter in the past but now run into a snag. I have about 2.2 # of starter. How do I feed this. I’ve tried replacing one cup starter with 8oz flour and 8 Oz water but the results I get with the action is not near with the action when I was first feeding the starter.   Now it takes forever to ferment and bubbling is weak not as it was. 
what am I doing wrong 

thanks for any help