Dice potatoes and place in saucepan. Fill with water cover over 1".
Boil water medium high.
Add 1 tbsp salt, reduce heat to medium and simmer. Stir until tender about 8 minutes.
Drain and transfer back to pot.
Add vinegar. Toss gently and let sit 20 minutes.
In medium bowl stir potatoes, celery, mayonnaise, relish, onion, parsley, mustard, rest of salt, pepper, onion powder, eggs.
Cover and refrigerate until chilled.