It is important to understand that TDS is not a measure of microbiological purity, it is simply a measure of dissolved solids like useful minerals and salt.
The natural organic coconut shell material of which our activated carbon filters are made, adds a tiny amount of beneficial calcium and magnesium to the first 50 litres of water, and then purifies up to 4,750 litres of fresh, pure water with no effect on the TDS level in your water.
If you have a filter that claims total TDS removal, it does not mean it is purified water. The water can be loaded with bacteria and viruses, but show O ppm TDS on a meter.
Finally, we would refer you to the World Health Organisations recommendations for drinking water, where they state the optimum TDS level for drinking water is between 100 and 300 ppm.