Okay, I just measured the flow rate from the drain line with a gallon container. I gave it a 7 count to fill the gallon container, so that average's out to a little over 8.5 GPM I would guess. I called the public works department and asked them about water pressure and he new exactly where we were and said that we would probably average somewhere around 50-55 PSI where we are. He also advised us to set the softener at about 25 grains, even though the water test only showed 18 so I'm torn there on what exactly to set it at.
I'm not sure how pressure affects the flow rates through this DLFC button, could that be why we are pushing carbon through the drain line? I called the purchasing company and they are sending me a 5GPM button to try. Is this the correct solution? I don't want to keep rinsing carbon down the drain.
I also checked the temperature of the cold water. It is about 53.8 degrees currently. I noticed while searching the forums that temperature was discussed a bit in these instances so wanted to provide this information as well.