Is taking a potassium supplement necessary aside from your daily food intake if you lift weights six days a week?

No : If you are lifting that religiously, you are surely trying to optimize your diet. Potassium is very common in normal foods, such as oranges and bananas, potatoes, tomatoes, etc. If you're eating a balanced diet , there should be plenty of ingested potassium. Good luck.

Potassium: Typically no -- diet potassium is easy to acquire from fruits and vegetables that are rich in potassium; these include citrus fruits, tropical fruits, juices, tomato, potato, peaches, apricots, melons, etc.