We have Sierra Reverse Osmosis Drinking Water System with 2 Gallon capacity tank. Earlier we used to get close to 1 Gallon water after the tank is filled. Now we are getting 16 to 32 Ounce only and we need to wait for 1 hour to get 16 Ounce agian. Looks like there is some problem and we are not able to identify the same. I changed the filters an year ago and we have this problem for the last 6 months. Any suggestion to fix this problem is appreciated.