I'm assuming Nature's Way is similar to Nature 2.
You have to put in dichlor (chlorine) any time you replace your Mineral Cartridge. This makes sure that you get your spa started off right, with plenty of sanizier (minerals) in the water.
It's always good to have a bottle of chlorine at your house, this can be your "secret weapon". If you have party or heavy use, or you just forget to add your shock to your spa, you can use chlorine now and then and help get it back up to speed without having to drain it.
As long as you're not using chlorine all the time, you won't ever notice a smell, just simply add the chlorine and run the jets with the cover off for 15-20 minutes.