Add water and onion to saucepan and sauté over low heat until transparent. Add yellow split peas and additional water. Cover and bring to a boil. Reduce heat and simmer, stirring occasionally for 35 minutes or until the split peas are soft. Add potatoes, carrot celery and cumin. Bring back to a boil, reduce heat and simmer until vegetables are tender. Add additional water and salt substitute seasoning as needed. Serves 4