I have added Laguna Peat Granules into the substrate. They are sold in a bag usually used for filters on ponds. They are basically peat moss compressed into rocks so arent as messy as bulk peat. If you take it and boil some r/o water then add the granules and hot water into a bucket it will sink faster. I can tell you plantes love it. Most of the roots drive right through and around them.
Some people wont like this type of use because it does not look as neat and tidy as a tank with Miracle capped with sand or all Amazonia tank, but PLants love it.
I have had success with Seachem red bottom layer. Then Peat Granules then topped with ADA Amazonia and some Humalite (like Leonardite but comes from fresh water lakes and also adds Humic Acid to Tank). The Humalite is rock hard form and does not noticibly dissolve, more dark brown colour.
Over time it all gets mixed up plants are happy