RODI production rate slower after upgrade

[Cell]

I recently upgraded from a Liquagen space saver 4 stage 100GPD RO/DI unit that would fill my 2.5G container in 23 minutes to a BRS 5 stage Premium Plus 100GPD RO/DI unit that is now taking about 35 minutes to fill up the same container at 60 psi with a 1:3 rejection rate. Why was the 4 stage producing water so much faster and from what I can tell, more efficiently than 1:3? It seems the new 5 stage is producing at the advertised rate of 100 GPD but the 4 stage was producing more like 150 GPD for some reason?

 

[dank reefer]

Is your flush valve in the off position?

 

[HuduVudu]

Older membranes are more permeable.

 

[Cell]

Yep, the handle is perpendicular to the valve. For some reason it seems the 4 stage was producing 150 GPD even though the membrane is rated for 100 GPD. I never really measured the rate until changing it out for this 5 stage and seeing how much slower it's going now. I upgraded because I needed a new membrane and pre filters and wanted a full sized unit not a smaller space saving unit, but maybe I should have stuck with it.

Do smaller chambers = higher psi? Maybe the space saving 4 stage was running at a higher psi than than the full sized 5 stage?

 

[Cell]

Older membranes are more permeable.

Its always run at pretty much the same rate.