It does not matter what the filters look like, are they doing the job? You cant tell this by the look. Yes an inline TDS
meter does save a little time but it only takes me a couple of minutes every couple of weeks or so with a small hand held meter. My RO
unit has been running for over 3 months now and has not come off the 1 ppm TDS
yet(with a 90 gal
top up water changes ect).
Mine is also puchased from Aqua-safe, no complaints. It also has a built in flush system in it, works well to prolong filters. One thing don't exspect to get your best reading the first time you run it, it takes a couple of days to break in the filters.