Sink Water draining into DW
I am having a couple of issues with my sink drainage. I had a new Waste King disposal installed. At the time of installation the sink was draining slowly but it appeared that it was because the splash guard (black rubber flaps at opening to disposal) were preventing the water from flowing quickly. When I put a spoon or something to push the flaps down to make a wider opening, there are a few air bubbles and then the water flows at a decent speed. The plumber who installed the disposal said this would improve as the flaps became more flexible but that has not been the case. Over the past couple of months we have noticed water at the bottom of the DW. We thought it was not draining properly but now we are realizing it is the sink water that is filling into the dishwasher. It is possible this has been happening since the disposal was installed but it is getting worse. We often run the disposal to help draw the water out of the sink.
I have attached a picture of the "high loop" set up of the dishwasher drain hose. I know nothing about plumbing but this seemed to be the cause given in for water in a dishwasher in my internet search. Is this problem occuring becasue of a plumbing issue or a clogged drain problem? Again, if I push the splash guard flaps open the sink drains at a pretty decent rate. I will post another picture of the plumbing to the disposal if that helps diagnose. I need to know whether to call a plumber or a drain cleaner specialist. Thanks