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.
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.
Remove from hot water, cool, peel and chop.
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.