When I built my pool 2 years ago, I got upsold so I have a Nature 2 Fusion, which is a combo in-line chlorinator and also a mineral cartridge.
First of all, I'm not using the in-line chlorinator at all because I've adopted the Trouble Free method...bleach only for me.
The mineral part is what I'm wondering about. When I purchased, I was told the mineral cartridge works using the same concept as a wishing well, or a fountain with coins thrown in. The minerals from the coins help to sanitize the water. I was told this would help with my pool as well, and would also help the water have a better "feel" to it. The replacement cartridges are expensive, and it's almost time for me to order a new one IF I KEEP USING IT. Looking for feedback here to see if anyone wants to chime in.