Hi, I've decided to try a planted aquarium for the first time and have been lurking around here for the past month or so gathering information. I have a 50 breeder that I want to turn into a high light, pressurized CO2, planted tank and I was originally planning on using Eco-complete (or similar) for the substrate.
What I wanted to ask was: if I'm dosing daily with dry ferts anyway, is there really any point in using a substrate with nutrients already in it? Would I be better off to just use sand or gravel for the sake of saving a few bucks (this project is getting expensive) and try to provide the plants with all necessary nutrients by means of ferts (which I will need either way)? Or another way to put it: what effect (if any) does using EC (or similarly enriched substrate) have on one's fert regimen?
EC isn't enriched, its volcanic rock and the ferts are naturally inside it, but many people claim the roots cannot extract the ferts. I think the company claims the acids that roots normally secrete break down the EC and release the ferts from the rock.
Some people claim the way sand compacts makes it hard for roots to grow. Supposedly the mix of large and small pieces in EC gives roots both space to grow and surface area.
My own gravel and rock substrate was struggling until I added root tabs, now the tank is slowly turning into a jungle. But the main reason gravel and sand aren't supposed to be good choices is CEC(cation exchange capacity), not lack of ferts because that can be remedied externally. High CEC means the substrate is negatively charged and has a high surface area so many positively charged(cations) molecules of nutrient stick to it and later become absorbed by the roots.
Sand and the quartz gravel have almost zero CEC. Peat has the highest measured CEC, its so high I'm suspicious of the figure. Clay is the second highest which is why good topsoil always has to have some clay in it. EC has a good CEC but not as good as clay.
So in theory if you get a substrate with high CEC all the nutes in fish waste and added ferts will stick to it due to electrical charge and then the plants will take it off the surface of the material as they do in nature.
I think this covers the whole thing, please mock me if I am wrong.