Questions about Haydite as a substrate
I am new here and relatively new to planted aquariums. I just got a 150 gal tall tank that I want to plant, and have been doing some research on substrates. I currently have a 75 gallon planted that has been up for about 2 years, and it has a topsoil substrate capped with gravel. The plants seem to grow ok in it, but I don't like the muddy mess it makes when I have to move plants.
So, after some research, I think I have decided on haydite, but I have some questions. From what I gather, haydite has a a good CEC rating, and will absorb nutrients from the water column, and then release them back slowly to the plant roots. Would I still need to add ferts, or will it become self sustainable once it fills to capacity and starts releasing/reabsorbing nutrients? If I need to add ferts, can I add them to the substrate in powder form? I was thinking of adding laterite, dolomite, potassium chloride, and horticultural charcoal to the bottom of the tank, and then capping that with 3" of haydite. Would this be ok? Also, there is a brand of charcoal I can get here called "Cowboy Brand". It is 100% natural hardwood charcoal, with no additives. Is that the same thing as "horticultural charcoal"?
Now, a question about the charcoal - is that meant to be a source of carbon? Will that replace injected CO2? I really don't want to run CO2 in this tank.
Thanks in advance, and I am really sorry for all the questions. This is turning in to a very expensive tank to set up, and I want to get things as right as I can so I don't waste money and end up having to tear it down and re do it.
Ps. FYI - I found the "H" size haydite at a local concrete plant. The cost was $12 per 5 gallon bucket, with each 5 gallon bucket covering approximately .67 cubic feet. ( 3 buckets will do my 8 sq ft tank to a depth of 3") I contacted the manufacturer of the haydite, and they said it will not break down in water, and in fact, they use it in water filtration systems. This is what made me decide to go with haydite over clays.