Hi Dave,
Not sure how to adjust psi, it came pre-set so I haven't looked.
I have a 300gpd RO system from RO-Man which I have had since Feb 05 the original pump that came with it lasted until a few weeks ago so not bad. Also I did upgrade the 300gpd to 450gpd when I changed the membranes last year...so mayby why I get a bit more water now.
Thinking about it I never really noticed the differnece when I changed from 300gpd to 450gpd last year, but with this new pump, looks like it makes a difference.
Steve G