1. Bring a large pot of salted water to a boil. Add potatoes and cook until tender but still firm, about 15 minutes. Drain, cool, peel and chop.
2. 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 10 to 12 minutes.
3. Remove from hot water, cool, peel and chop.
4. In a large bowl, combine the potatoes, eggs, celery, onion, relish, garlic salt, celery salt, mustard, pepper and mayonnaise. Mix together well and refrigerate until chilled.