I’ve had the 4 stage RODI system for well over a year now. Before I changed the media the TDS was reading 1 in and 0 out. After I changed it out for all 3 stages of new media it now reads 2 in and 2 out. Why is this? I tried flushing out the membrane for 10 minutes with no change. I changed the media out maybe 2 months ago. Resin hasn’t changed color but the 5 micron stage has turned dark yellow. I need help fixing this. Thanks guys