yep ADA aquasoil can make toninas easier.
what I think toninas need most is low carbonates. soften the water / make KH very low and belem and fluviatilis are very easy to grow. dont forget ample CO2.
the harder ones like uaupes, just require balanced ferts like an erio. low KH still applies.
Once eco complete has aged, it is more than capable of growing toninas. I dont think toninas care much about the substrate, just dont like carbonates in the water.
I think Amazonia I is probably the most widely used substrate for toninas and erios. If you have slightly harder water you might try Amazonia II which is better suited for softening and acidifying aquarium water.
toninas are not root dependent even if you use aquasoil you will notice very little root growth. I can grow it in plain old SMS its more about the water column with this plant. soft water and plenty of CO2 is the key
I grow Tonina Belem very well in my tank and I only use regular river gravel with some laterite mixed it. I put a couple of root tabs under a bunch of them though. I use high PC lighting and CO2 and it grows very well. My uncle who has the same setup as me except he uses eco substrate is able to grow it also, but it does not grow as well as mine. Some yellow leaves here and there, but it does not die. Same water specs as well.
Soft water and lots of co2, whoever said that first gets a prize. A couple people in the Pittsburgh club (including me when I was there) grew T. fluviatilis and Syngonanthus (only T. fluviatilis is really a Tonina) in Soilmaster and even plain gravel. In the latter case, I wonder if some blackwater extract would have a beneficial effect.