Another nano!
That should be fun.
Is that rock very porous though? Looks kinda solid and flat. May be ok; I don't have experience with that kind of rock.
You asked about my 20 gallon - I have about 30 lbs of rock or more in it.
Nitrates have been 0 for a while now. Hardest thing I've had is keeping the alk up. I would get it up there and then do water changes with NSW which lowered the alk again.
Now I am getting it back to where I want and considered buffering the NSW before I add it next time.
Since I am using my old halide lamp from my 30 gallon on it (150w) I also am now dealing with heat problems. Fans are helping, but I ordered an IceProbe Chiller with the controller from our sponsor Premium Aquatics.
This whole time, I haven't had fish, so talk about going slow!

It's helped get me back on my feet though. And while the tank is hot, I am glad I don't have them now.