For info.... the pool is a 17 years old, outdoor, uncaged pool that has never had the water replaced. Lots of tree droppings end up in the pool.
It has patches of very slight stains that usually go away with Jacks Magic Metal Control Purple treatment. (I tried an ascorbic acid treatment earlier this year attempting a more permanent solution and it didn't really affect the stains long term). I was looking to start back up on metal control. The best prices for the Jack's magic is around $24 a bottle so I was looking for a cheaper alternative that may produce the same results.
And with your question, I assumed that since they sold a salt pool version that I would need a salt pool version. So if I don't need a salt pool version for metal control, I am ok trying out something cheaper.