Aloha Kitty! (See...I CAN exercise self-control!)
To answer your question, I would have to know more about what type of water you have...people with really hard water DO get calcium buildup on the plates of their generators. Where I'm from, we don't have any calcium in the water (the island is young and still being built!), just silica. So I don't have much experience with those "anti-scale" products. But I do know that there ARE chelating agents and sequestering agents that can help if you have a naturally high calcium concentration in your water. That's probably what scale free contains.
What kind of reading do you get on a Calcium Hardness test?
Aloha!