Sediment and carbon block filters have nothing to do with TDS, they are there to protect the RO membrane from TSS, suspended solids or big stuff. TDS or dissolved solids are in the 0.0001 micron range so pass right through them to be removed by the membrane.
When you need to replace filters, remove the old sediment and carbon filters, disconnect the line leading from the carbon block up to the RO membrane at the RO end, rinse or wash the empty canisters in hot water, place 1 cap full of regular unscented bleach in the sediment filter housing only, screw the empty housings back on and slowly fill the canisters until water starts to come out of the disconnected line. Let it sit and disconnect the system for about 5 minutes then flush it out unti all smell of chlorine is gone.
Once disinfected, leave the line disconnected and install only the sediment filter leaving the carbon canister empty and run a gallon or two of water through the sediment filter to rinse any glues or binders out so they don't foul the carbon. Next install the carbon block and again run water through it to rinse any carbon fines or dust out so it does not foul the RO membrane. Reinstall the 1/4" line to the RO housing and you are ready to make RO water. When installing a new DI cartridge or resin run the first 1/2 gallon or 3 or 4 bed volumes to waste until you see 0 TDS and you are set.
It is important to flush each filter individually so you don't foul whatever is downstream and it is even more important to disinfect the system to reduce the chances of bacteria or virus growth inside the system.