Ok, I'm gonna counter the contrarian

You are only considering the hard costs of Cl vs cost of installing and price the unit in your ROI.
-What value do you put on your time? Time to pick up the the chlorine, The additional time it takes to manage a non SWG Pool. for me that's verifiable. I live by hourly billing. Compared to before the SWG and after, I paid off the $1500 outlay in the first year.
-What value do you put on a higher quality of water. The value of knowing my daughter's skin isn't going to break out from swimming is priceless.
-What value do you put on getting more out of your SWG beyond your estimate. My break even on cost time frame was at about 3-4 years.. by that measure I have been getting free chlorine for more than 10 years.
Given all that together installing an SWG was the best home improvement purchase I've made ever. I will concede one added cost that I found over the years. There is an ongoing increased entertainment cost from pool parties and guests because given a choice they all want swim in our pool.