There are only 3 EPA approved methods for pool sanitation in the US -- chlorine, bromine, and biguanide. What someone does in their private pool may not be regulated, but it also may not be safe either. Further reading:
alternative-sanitizers-and-chemical-free-pools-the-truth-t3025.html
Most municipal water sources have chlorine in the water and it is drinkable ... so not sure what the point of that claim is. There are other chemicals in the pool water that are not good to be ingested in large quantities. There are lots of threads here discussing using the pool for drinking water and in general it is not a good idea.
All adding CO2 into the water will do is lower the pH (EDIT: actually the CO2 lowers the pH, not raises it like I first said)
Your salt pool is a chlorine pool (the cell just "creates" the FC from the salt). In reality your water is around 3500 ppm of salt, the ocean is 35,000 ppm of salt ... so it is not really "salt" water. In fact it is not uncommon for not SWG pools, to have up over 1000 ppm of salt in them as all forms of chlorine add salt. And some, like myself, add up to 2000ppm of salt just to improve the feel. If you switch to "fresh" water, you will need to use one of the 3 chemicals listed above to maintain clear, safe water.
In general for outdoor pools, chlorine is the cheapest and most effective way to maintain a swimming pool ... whether you use a SWG or not. The use of UV or ozone or minerals, costs extra money (since you still need the chlorine) and could potentially cause additional problems (like metal staining).
EDIT: That product is just another one of the mineral setups that adds copper and titanium into the water. If the pool is not properly balanced and the levels of metal get high ... the pool surface will stain and blond hair may turn green due to the copper. This is not effective protection against person to person transmittal of bacteria / viruses.
EDIT2: do a search for "clfree" and you will find some threads. Here is one:
pool-spa-system-sanitizers-t40308.html?hilit=clfree