I work with a so-called mixed-bed filter, which is filled with a mixed bed of synthetic resins of two kinds. This method produces at high speed large quantities of fully demineralized water (identical with destilled water). The cartridges must be treated (revitalized) professionally. You can not do that yourself.
The water you obtain is of the purest possible quality (near to H2O). So, you still have to add a tiny amount of minerals again, change the pH to acid values (f.i. by peat) and add humic substances in order to receive a sort of blackwater.
This ist the best, quickest and most consequent technical way presently at hand.