After getting home from Michigan I launched into the big clean up - two major water changes in the main tank, addition of some rocks, and the addition of a lot of new plants. I also changed one of the bulbs in the "breeding" tank to a compact fluorescent bulb, since the original bulb had blown.
When I went to Petsmart to look at plants I realised that they had fairly cheap 10 gallon tanks (sans heater, pump, lights, or lid). Since I was already thinking about setting up something to try to revive all the uprooted plants in the main tank (that had taken to a floating existence), it seemed like a really good idea. So I bought a 10 gallon tank.
Since I was only planning to use the tank for plants, I figured I could use a soil base. Unfortunately, without thinking too much I used potting soil. Bad idea. It turned out that potting soil is (a) not soil (it's wood chips and compost), and (b) it floats. So that didn't work too well. I later read that if you use soil, you need to add about an inch of gravel above it (and, I suppose, make sure the gravel layer isn't disturbed when you add the water). Anyway, I ended up getting some aquatic plant "soil" from Home Depot - it's porous, fired clay. Hopefully it will do the job of a rooting medium.
Once I established the tank I realised that it needed a nitrogen source (fish waste) so I eventually added a few "baby" Macropodus. Since they are air breathers, I figure the lack of circulation shouldn't bother them. Now I just have to ensure adequate light and CO2 - not the easiest tasks in the world.