Bring a large pot of salted water to boil. Add potatoes and cook until tender but still firm, about 15 minutes. Drain, cool, peel and chop.
Place eggs in a saucepan and cover with cold water. Bring water to a boil; cover, remove from heat, and let eggs stand in hot water for 12 minutes. Remove from hot water, cool, peel and chop.
In a large bowl, combine eggs, celery, onion, relish, garlic salt, celery salt, mustard, pepper and mayonnaise. Gently fold in potatoes, attempting to keep them from falling apart. Refrigerate for at least 4 hours.