Bring 5 cups of water with 2 tsp salt to a boil on medium heat.
Add in your pasta and cook until al dente, 10 minutes, or according to package instructions.
Drain your pasta and rinse under cold water. Add more cold water to cover the pasta and set aside.
In a small bowl, add mayo, vinegar, sugar, 3/4 tsp salt, black pepper, mustard powder, and garlic powder to form your dressing. Mix until well combined.
Drain your pasta and add it to a large bowl.
Drained the canned tuna and add it on top of the pasta. Ensure to flake the pieces for even distribution.
Next, add in your diced celery, red onion, red bell pepper, and your dressing. Mix until well combined.
Refrigerate for a minimum of 1 hour and enjoy.