Thanks Ben (I should have looked it up) now I do know what a Fusion Nature Two is.

billie:
I still think SWCG is a better choice. Trichlor can be a valid choice for chlorination but can't be used as the only source of chlorine. It adds stabilizer as well as chlorine which is good to a point but as stabilizer level increases so does the required level of chlorine necessary to sanitize. Trichlor also tends to push pH down which would have to be brought up.

Copper can kill algae and silver can slowly kill some (not all) harmful bacteria. The Nature 2 system still requires chlorine for sanitization and oxidisation of stuff that gets in / is left in the pool. Silver and copper can stain pools and swimmers (copper makes fingernails and blonde hair turn green).

I don't believe that it would be possible to maintain extremely low chlorine levels with the trichlor feeder continuously increasing the stabilizer level. And since you'll need to chlorinate the pool anyway, I can't see how buying the copper / silver cartridges could save any money.