
My 5-stage reverse osmosis system is 16 years old. I just disinfected it and changed all the filters and membranes. The last water came out at 33ppm. It turns out that the check valve is defective. After installing a new YZM check valve, the drinking water level drops to 24 ppm. In addition, the non-return valves adapt perfectly to the membrane body with a little Teflon tape. Highly recommended.

NANPU DFR-02 1/4" NPT Air Drying System - Double Air Filters, Air Pressure Regulator Combo - Semi-Auto Drain, Poly Bowl
20 Review

NANPU 1 FRL Air Filter Regulator Lubricator Combo With 0-150 Psi Gauge, 5 Micron Brass Element, Poly Bowl & Semi-Auto Drain - Metal Bracket Included
20 Review

NANPU Air Drying System With Double Filters And Pressure Regulator Combo For Clean And Controlled Air Supply
18 Review

NANPU Compressed Air Filter Regulator Combo: Brass Element, Semi-Auto Drain, 0-150 Psi Gauge, And More
21 Review