From personal experience, I would not waste your money on so-called plant substrates. For the type of system you are intending there will be no benefit
Sheesh, I forgot to mention our tank is 24" tall.
Good do point about the fake plants and the room equipment takes up! I hadn't thought of that.
This may be an aside, but I didn't elaborate
It's normal and will go away with time.
I'm John, I have a 55 gallon fw tank that is 3-4 months old; I'm new to the hobby and I'm still in the process of stocking my tank