The teas are not a source of nutrients, rather, they work in cooperation with the plants root system to make them stronger and more efficient.
Teas are great, the plants benefit greatly from it. What is the price? It is inexpensive to brew your own actively aerated composite tea with 4 products (Actually you buy the ingredients and breed more of them, technically.) Incredible boost to the plants immune system. Thing are indestructible with a nice microbe population.
All you need is ZHO powder, aquashield, Earthworm castings, some molasses, and an airstone. It comes out to just a few cent per dose. If you can't be troubled, just buy the tea from the hydro guy. It will help immensely. I have also just added seaweed to my feedings, and there is academic research supporting its immense benefits.
Be certain you are using completely dechlorinated water, as that can wreak havoc on bacteria populations. If you have chloramine in you're water, it is nearly impossible to offgas and you would have to look into using sodium thiosulfate or Ascorbic Acid to eliminate it.