You have a vinyl pool and your water's CSI (assuming 3400ppm salt and 75F) is -0.56. There is no danger of calcium scale developing at all in your pool. There is a trend among GA pool owners to have issues with iron in their water (either from municipal supplies or blown in from iron-rich Georgia soil) so a scale inhibitor would help to keep iron staining to a minimum. However, if you have never had any problems with iron in your water then there's also no need to use a scale inhibitor.
I certainly would not add anything with those good numbers. In fact, your CH should probably come up a little to about 250. It will probably do so on it's own or you can hurry it along by adding some. Keep your pH where it is and you should never have a scale issue.
That is not to say though that calcium scale can't develop in a vinyl pool with elevated CSI. No, we do not recommend using a scale inhibitor to avoid scale, we recommend keeping your water balance to avoid scale. More here, Pool School - Calcium Scaling