This water filter is a game changer and it was less than $40! The TDS meter measures the amount of organic and non organic material in water. Although there are ranges for what is deemed healthy. We still do NOT need large amounts of minerals in our water. The majority of these minerals are way above what is needed for our systems and filled with harmful amounts of chlorine and fluoride that our bodies have a hard time processing and that clog important receptors needed for healthy hormones. Taking all minerals out with this filter will also remove harmful bacteria, viruses, and hormones that can pass through normal tap water and filters! Several sizes to choose from, I got the 32 cup filter. You can also purchase more filters and the life of the filter depends on how bad your water is. My water is way above what is deemed safe! LTKfindsunder50 LTKhome LTKVideo