Substrate for larger planted tank
Ok so small dilemma, I have a large tank 7ft long x 2ft deep x 2.1ft tall was previously a marine tank. I want to go for a planted tank with C02, I will have high lighting as im reusing 2x Eco-tech XR30's with diffusers so high lighting. the plants I would like to keep are: Javamoss,dwarf hairgrass, Hemianthus micranthemoides,Cryptocoryne, Echinodorus bleheri , Vallisneria Spiralis, Ceratopteris thalictroides, duckweed, Alternanthera reineckii 'pink', Alternanthera reineckii 'Mini, rotala rotundifolia and Rotala Macrandra. (Seen this can help sometimes)
Now money is partly an issue but if I need to pay more for a substrate I will. I have heard that high CEC would allow me to use fish poop and water dosing to provide nutrients, root tabs would be harder to do in a tank this size when everything has grown out. I dealy I would like a substrate that would last as long as possible and I keep hearing mixed things about Eco-complete, Stratum turns into a clay mush, and sand would stop nutrients going to roots , with gravel being a poor CEC value and bad for roots.
so Wise fish tank people what substrate should I use ? dirt capped, sand , gravel, volcanic stuff. please help xD