Very Simple Salmon Chowder

Name: Very Simple Salmon Chowder
Ingredients: 6 tablespoons butter, divided; 2 large fat leeks, white and light green parts only; 4 cups peeled potatoes cut into a 3/4 inch dice (I used 3 large redskins); 3 tablespoons flour; 4 cups clam juice or fish stock; 2 cups half and half; 1 1/2 pounds boneless, skinless salmon cut in one inch cubes; 1 cup minced fresh dill; Salt and white pepper to taste