Yeah. 90psi is about the limit. The seals will hold, but the membrane will get ruined if I go much higher. My tap water is hard, had high silicate and fairly high chlorine. I think they recently switched to chloramine now, but when I started running catalytic carbon for the first carbon stage, that seemed to really extend membrane life and enhance rejection rate. My membrane is giving me like 99.7% rejection these days. Above the advertised rate.