I posted here a while about adding plants to a fish-only tank, I got
some good advice on what to do, but now I need more specific help.

For my 20 Gallon long (12 inches high) tank, I decided to go with a 55
W compact fluorescent light and no CO2 (for now), but I'm confused
about gravel/substrate. I have 1.5 inches of mixed size gravel (1-4mm
dia. aprox.) that used to be part of a UGF system but now sits on the
tank bottom. Now what do I do? I've decided I'm going to need to add
some sort of substrate (fluorite, etc.) but how?

Do I layer it under the gravel, or mix it up? As my tank is only 12
inches high (20 gallon long) will I have to remove some so I can fit
the substrate? I don't think I can fit more than 2 inches of gravel
in my tank.

Also, does any of this matter if I just keep the plants in the pot,
and cover it with gravel?

Ken