I'm going to echo
@Matt. Again. (I seem to be doing that a lot recently!
). I think it is a good article. Although I won't be changing my substrate, again, any time soon (or ever), I will refer back to the root tab information.
For information, I have Caribsea Eco complete. I had an issue with my tank at first set up, so it inadvertently got washed. By otherwise have been very happy with it. But I used it as a base under gravel and consequently spent nearly 8 years looking at it thinking "there's too much substrate in there". I finally completed a refurb of my tank, and (in sections) removed about 2/3 of my substrate. I then sieved some of what I'd removed and put the small grains back in. I used a 2mm diameter sieve because I wanted it to be close to sand while still reusing the substrate I already had. So now my substrate is approximately 3-4cm deep (it varies due to inhabitant remodeling!) and predominantly the caribsea eco complete because the gravel water generally grains larger than 2mm.
If I was starting from scratch again, I think I would look into one of the sand like complete substrates. Partly because I've decided that I like the dark substrates.
I do also have sand in my tank (a recent addition at the time of the refurbished). But I've used that as decoration and haven't specifically planted anything in it. Where it looks like there are plants in the sand at the edges, there is eco complete underneath. Because smallest grains sink to the bottom, I don't know how long the sand will stay on top. And I've not had sand in my planted tank long enough to know how that might affect the growth. Other than to sympathise with
@fcmf at how difficult it can be to get plants to stay in the sand.