I keep a lot of rare (to the US hobby) plants, mainly from Borneo and Indonesia, so I make a mix that is very acidic to mimic their natural environment. I tried a version of ABG mix previously and I just didn't get the plant growth I wanted, so I started experimenting. It also helps when you have a few friends who work in the horticulture field to bounce ideas off of.

I have considered utilizing laterite for an extra boost of iron, but with everything else I have in the mix, I don't think it's really needed.