I don't like either. I prefer plain salt cells.

Mineral feeders like Nature2 add copper and silver. Chlorine is faster than both so neither add to chlorine's capabilities. Neither will reduce the amount of chlorine a pool needs. The Fusion system adds it to the salt cell. The manufacturer and dealer want the money for new cartridges twice a year and the cartridges are quite expensive and needless.

CL-Free adds copper ions. While it can reduce the chance of algae, it can stain, causing blonds to have green streaks in their hair, green decks, etc... There is no other residual left in the pool so person to person transmission of things like eye, ear, and skin infections can happen. IMHO, they are dangerous to people. Whoever is selling it, avoid doing business with them. They don't care about anything but the money.

Thoroughly read the following thread link at the bottom in which CL-Free and I got into it. I think you will see what I mean.

Here is a link that might be useful: CL-Free vs Reality

I have the CL Free system. The good, it kept our pool algae free through an Arizona summer. The bad is the quality is awful. we have had problems with the electronics, the chamber, the hardware, everything. The hardware failure caused my yard to flood! Not good. And keep in mind, we have only had this thing for 5 months!

The copper also turned my pool copper green along with my wife's hair. The $150 copper lasted less than 5 months, the $400 titanium is corroding badly. When we try to get support, they have a list of excuses and wild goose chase items a mile long. We have had the same problems since install and they are unable to resolve.