To Peat Or Not to Peat
I have found a light covering of peat under most substrates to be helpful; I cannot say I have any real idea as to how long the effectiveness. It does seem to continue to leach into the water for months.
I have actually found peat moss tea a rather effective treatment, additive for soft water environments and it is a lot cheaper than the “black water extracts.”
The other recommendation I would make if you want an enriched substrate is to add some Osmocote under the substrate for slow release nutrients. I am also partial to Tom Barr’s worm poop mixture.:gw