1. Season salmon fillets with lemon pepper, garlic powder and salt.
2. In a small bowl, stir together soy sauce, brown sugar, water and oil until sugar is dissolved. Place fish in large resealable plastic bag with soy sauce mixture and refrigerate for at least 2 hours.
3. Preheat grill for medium heat
4. Lightly oil grill grate. Place salmon on grill and discard marinade. Cook salmon for 6 to 8 minutes per side or intil the fish flakes easily with fork.