aquasafe ro unit high tds

[Delphinus]

I would suspect membrane. It should be bringing the TDS down to <10 within a couple minutes. That said, how long are you waiting? At startup there is typically a "TDS surge" which can last anywhere from 5-10 minutes. Usually what I do is flush the membrane for a good 5 minutes and then check the TDS. If it's still 200ish after 5-10 minutes though, then the membrane is toast.