I just ordered the Spectrapure double DI system to add after my RO system. Thanks for the recommendation.Diatoms are good in my book, at least compared to dinos . I would try to get zero TDS however. Mostly to remove things that we don’t measure.
I am a fan of Spectrapure systems. A double DI that piggybacks after the RO would be great. More $$ up front, but lower total operating costs IME.
Good luck.