I mean, am I if I’m just trying to plan ahead and get a realistic idea on what it would be costing? If I’m gonna have to change filters every 2-3 months then yeah, I’d rather not spend that much at that point. If more 6-12months (preferably 12 at least for carbon and membrane), then it’s more ideal for me. That’s why I’m trying to be SMART and plan ahead and ask all the right questions BEFORE I commit to it all.Not to mention you’re way over thinking this second post about rodi if this is too expensive for you to provide perfect water this is the wrong hobby for you. Not trying to be mean but water is their home and why would you not want it to be perfect. Kind of like a non smoker buying a smokers house just bad decision making.
That said, a couple TDS is unlikely to create an unpleasant habitat for the fish because whatever IS in that TDS would be such an insanely diluted PPM that it would most likely be insignificant. It wouldn’t be as if you were running straight tap water at like 100+ TDS. Still, the lower the better obviously, but from what I’ve learnt so far (and I could be wrong) I don’t see extremely low levels of TDS slipping through being anything truly devastating to your Tank.