membrane should ideally remove 98%+ of the tap water TDS
membrane performance will vary).
removes what the RO
The pre-sediment and carbon blocks usually have a negligible impact on TDS
reduction. If by filters you mean these, then you would not get a reduction in TDS
water if you changed out the filters.
You would get a reduction in RO TDS
if you are replacing an old RO
membrane with a new one.
As an example if the TDS
of the tap water is 275ppm, it would be 275ppm or very near it after it passes through the pre-sediment and carbon blocks. After passing through an RO
membrane with a 98% rejection rate the TDS
of the RO
water is reduced to about 5 or 6ppm. The DI
stage reduces this to below 1ppm. (registering as a "0ppm" on most TDS
meters that cannot detect levels lower than 1ppm but greater than 0ppm).