Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
3         cups          water 
1         cup           soy sauce 
1/3       cup           brown sugar (substitute by brown sugar twin) 
1/3       cup           white sugar (substitute by sweetener) 
1/3       cup           kosher salt 
1/2       teaspoon      onion powder 
1/2       teaspoon      garlic powder 
1/2       teaspoon      pepper

Preparation:

Stir until ingredients are dissolved. Marinate fillets overnight. Air dry fillets and smoke as usual.