Awesome. Congrats on the new babies.
I was studying your setup to do my setup, took some inputs from this thread. But I opted for more plants since my tank is much smaller (3 feet).
Found those volcano rocks at a fish stop, those rocks are pretty expensive (approx USD4/kg) so decided it'd be better to invest in a chiller instead to achieve subtropical temperatures. It's gets pretty hot here in Malaysia.
Thanks for sharing the info, pics & clips.
Deen