I use Promix HP for my mix. I use this for about half my mix. I add more perlite just like @Calyxander. Promix is great because it has inert media (SPM “peat”) and aeration (perlite), but it also has lime for PH balance.
Peat also blows most other medias out of the water as far as CEC (Cation Exchange Capacity). This is the amount of nutrients the soil is able to hold. The pantry of the plant.