Hook up the pump and see what TDS comes out after 20 to 30 min ( to flush the protective coating off the RO membrane ) If you can test the water after the ro , before the di resin. It should be very low you only want the resin to remove 1 to 5 tds. Otherwise you will be going thru resin quite fast.
Stage 4:
Reverse osmosis high quality membrane (we offer 50, 75, 100 and 150 GPD membranes). The Vontron membrane holds up to 99% of contamination
from feed water. It successfully removes harmful organic and non-organic compounds, heavy metals and some bacteria and viruses.
Stage 5:
In-line demineralizing filled with high quality DI resin for complete demineralization of water. Openable housing - you can refill the cartridge with media on your own