I myself never use any kind of fertilizers. The fertilizer i get is from any bugs that die, Nematodes, Frog droppings and dead plant matter. Basically your tank is its own ecosystem. Springtails can be added to the tank and would break down any decaying or rotting plant matter.Plus depending on what kind of drainage you use, hydroton and leca(don't know if i spelled right
) is good to use in a sense it holds moisture from the water it is in contact with.So when your frogs and all that other stuff starts doing their thing, the nutrients will leach down into the drainage area and with hydroton and leca it will absorb that and basically release it when you would do a water change. Plants roots will grow in the drainage layer so it is a good thing. It is similar to a hydroponic system. Just think of it this way, your walking in the Amazon Rain forest and you see an area thats so beautiful you scoop it up and put it in a tank. The Amazon doesn't use fertilizers and its thriving with plant growth so why mess with a good thing.
Hope this helps
Sam