Troubleshooting RODI rejection rate. Do I need a booster pump?

[i_declare_bankruptcy]

I have the 5 stage BRS water saver 200GPD RODI system. Its stated minimum input pressure is 65 PSI; I'm getting 62 PSI at the tap. I live in a condo so no control over the water pressure.

It definitely feels like I'm getting closer to ~60-70% of the GPD (so closer to like 120GPD) with a lot of waste water.

I have an inline triple TDS meter; reading 450 at source, 0 after RO (this seems incorrect and I am going to fiddle with the probe to see if it's faulty), 0 after DI.

I am getting 42PSI after the prefilters (sediment, 2x carbon -- both were replaced with the appropriate BRS filters one month ago).

I've had this unit for over a year now and haven't yet replaced the RO membranes. I *feel* like it was performing better towards when I first bought the unit (which is why I replaced the prefilters) but I don't remember the rate I measured back then so I could be wrong.

I'm trying to figure out if I need to replace the RO membrane(s) or get a booster pump to help with performance (or do both). I understand knowing the TDS after the membranes would be helpful, I am working on trying to fix that now.

Thanks in advance!

 

[mdb_talon]

Looks like you are in Southern California so water temp i assume is not an issue(sucks making rodi when water is nearly ice cold!) I would get a booster and put it after prefilters. 42psi seems quite low.

An Ro membrane with even fairly heavy use should last 18 months minimum so i would start with the booster pump as it is going to be a benefit in any case.