i thought distilled is filtered?... i mean, there's two types right?... the distilled/purified and spring/mineral water?...
and yes, if you're a serious reefer.. invest in a RO system, DI optional IMO... ebay gots some good ones.. check out craigslist too... I got mine off of craigslist for dirt cheap and its been working great!.. TDS at 10 right now cause I'm overdue for some membrane changes...
FYI.. correct me of I'm wrong.. Tap water is around 200 TDS and safe drinking level caps off at 400 TDS?...