Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Pure RO does need a few minerals added, but not the complex recipe you are asking about.
GH (calcium and magnesium) = Seachem Equilibrium or Barr's GH Booster.
KH (carbonates, bicarbonates) = baking soda, or potassium bicarbonate
All other minerals = aquarium plant fertilizer: KNO3, KH2PO4, K2SO4, trace such as CSM+B
For the fish you list a very low level of minerals is just fine.
GH no higher than about 3 degrees is OK, unless the plants remove the calcium and magnesium so fast that the GH drops too much between adding it or water changes. You could add it with the other fertilizers in small amounts, if needed.
KH as low as 1 degree is fine. Nitrifying bacteria get their carbon from carbonates. Plants are the biggest nitrogen removers in a well planted tank, but I think it is a good idea to keep some bacteria happy, too.
I only use pH as a guide to see if things are stable, not as an absolute number in itself.