Thanks for the tips....I have an update.
I did buy the back flush elbow to at least give it a try but I don't have a clear shot to either tank so it really doesn't do any good.
I bought a chemical that the lady at Camping World said would work on the black tank but not the grey tank. The chemical ended up working a little for the gray tank but not at all for the black tank.
I left the chemical in both tanks for about 4 or 5 days. I did nothing for the black tank but really flushed out the water in the grey tank. However the gray tanks is clogged again....The black tank remains clogged. I am guessing at this point I am going to have to call someone in to pump both tanks out. Any clue how much that will cost me?