Quick take
Frizzlife lists ASR212-800G specifically for PD800-TAM4, with a two-year nominal life and current listed price of $89.99.
Correct system
Use ASR212-800G for PD800-TAM4. It is different from ASR212-600G used by PD600-TAM3.
Replacement schedule
The published lifespan is two years under stated use conditions. Water quality can shorten real service life.
Current price
Frizzlife currently lists the cartridge at $89.99.
When to replace sooner
A persistent drop in membrane rejection after flushing and first-stage maintenance can justify earlier replacement.