I have a 60l tank which I want to set up. I'm thinking of having a HC carpet but havent decided on other plants yet. When looking into it, eco complete and ada aquasoil seem to be the main ones recommended but I've heard that they're not necessarily great long term as they get mushy or lose nutrients. Are there any substrates which work well but don't degrade too much long term? My LFS recommended this but that's the one they sell. Would I need to put something on top of that one? They also recommended a clay one which they used in their plant tank.

This guide seems pretty good.

I will have a led light array and co2 and plan to dry start the HC. I would prefer to have a dark substrate I think.