Set includes 1x 5 micron sediment 1x 5 micron carbon block 1x 100 GPD RO membrane and 1x color changing DI filter.|Replace pre- filters every 6-12 months replace the membrane every 2-3 years di filter life is 5 000 ppm.|Reverse osmosis removes a large majority of TDS (total dissolved solids) but not enough of it. TDS can be lowered to extremely low levels by using a DI (deionization) filter. With our filters you will typically get ZERO to near ZERO TDS