Prep the seafood. Chop the imitation crab and defrost the fully cooked small shrimp. Set aside.
In a large mixing bowl add mayo, sour cream, lemon juice, Old Bay seasoning, celery salt, dill, and sugar. Mix well with a whisk.
Fold in the chopped bell pepper, onion, green onion, celery, and seafood.
Mix until combined. Taste and adjust seasoning with pepper, onion and garlic powder, if desired.
Spoon into a deli container or air tight container.
Chill the seafood salad in the refrigerator for at least four hours. Overnight is best, it really allows the flavors to meld together well. Enjoy.