Place a 6-quart Dutch oven over medium heat and add the bacon.  Cook, stirring often, until the bacon is crisp and most of the fat has rendered, about 4-5 minutes.  Remove the bacon from the pot and pour off all but 1 tablespoon of the bacon fat.  Add the butter to the pan and once melted, add the onions, leeks, celery and bell peppers.  Cook, stirring until the vegetables are soft, about 5 minutes.  Add the garlic, thyme and bay leaves and cook until the vegetables are thoroughly wilted, about 3 minutes more being careful not to brown the vegetables.  Add the flour to the pan and stir to form a roux. 

Once the roux is mixed, add the clam juice and half-n-half to the pan and raise the heat to high.  Bring the soup to a boil then reduce to a simmer once the liquid thickens slightly.  Season with the salt and pepper.  After the soup base has simmered for 20 minutes, season the shrimp with the Essence and add it to the pot with the mussels and salmon.  Stir well to combine and cook for 5 minutes, or until the mussels open and the shrimp are fully pink.

Stir the potatoes into the pot and remove it from the heat.  Serve the chowder in wide-mouth bowls garnised with the chopped parsley and green onions.