In a large stockpot, add enough olive oil to coat the bottom the pan thinly and saute the large diced white onion and large diced green pepper until translucent. Add lobster heads and shrimp shells. Cook until color starts changing and starts to look red. Add tomato sauce, white wine, and bay leaf. Add clam juice and water. Cook for at least 2 hours, then strain.
In a medium size stockpot, saute the small diced onion, and small diced pepper until translucent. Add rice, clams, mussels, bay leaf, and a pinch of saffron. Add all strained seafood stock and cook until rice is soft, approximately 20 minutes. Add shrimp, scallops, and lobster. Cook for approximately 8 minutes. Add culantro and season with salt and pepper.