Quick take
Frizzlife currently lists ASR212-500G at $76.99 with a two-year nominal service interval and PD500-specific fit.
PD500-only fit
Frizzlife identifies ASR212-500G as the second-stage membrane for PD500.
Replacement interval
The manufacturer recommends replacement around every two years, subject to feed-water quality and daily usage.
Current price
The current manufacturer listing is $76.99.
Replacement signal
A sustained decline in membrane rejection after first-stage maintenance is a stronger signal than age alone.