Most of those filters do not remove the stuff that is the problem, but it seems that Zero water is different, it actually removes TDS. The niggle is the cost of the filters. At ~300ppm, you might only get ~10 gallons of water for each filter, which is more than a buck per gallon. It would not take long for the cost of filters to pay for an RO system, and that cost is not that far off what distilled water can be bought for. OTOH, one might be able to reduce cost by using a combination of filtered and unfiltered to lower ppm into a more acceptable range. I can't use RO on my tap water because wasting most of the delivered water would be too expensive. RO systems waste a significant percent of the water they use, a lot of it is sent down the drain as salty bypass, while the good stuff is diverted to the tap.