I have been growing plants like various swords, c. wendtii, java fern, hygrophila polysperma, and jungle val using inert gravel with root tabs and a good dosage of fertilizer. I am setting up a new 75 gallon, and wondering if I should consider putting a base layer of nutrient rich substrate? Reading George Farmers book, he is very adamant on nutrient rich substrate. I don't plan to inject CO2 for the time being. Considering it will be a "low tech" tank, will I regret not putting in a plant substrate down the line? Is it something that can be done reasonably down the line once the tank is established? Thanks for any advice.