Hi Dan. Thanks for the comments!
Modifying for sand or fine gravel is easy.
Keep the airstone in if using sand and fill the fixed filter basket area that the filter sits in with smallish pebbles. This keeps sand out of the one way valve in the base. Remove the air pump, knot the end of the airline and add one or two extra one way valves into the airline to safeguard leaks.
The rest is straight forward.
You could use a Newattino Plus 10W heater in the tank. Really small and easy to hide behind something. I used a small filter that came with my Arc tank. It has a short spraybar on which I aimed at the surface for good movement
Hope that helps