Good answer, I forgot to mention that my goal was to breed some killies. Specifically, some of those black colored F. cingulatus that I showed a few weeks back. So yes, I realize it will get hot and that I will get some algae, but according to the Luke McClurg document, I want to do that to generate some food for the pending fry.
I probably will leave them above ground this year and see how it works out, but I certainly could bury them a little (I just hesitated to do so, because these tanks had a nice drain and the bottom and I would loose access to them if I buried the tanks any... don't know why I want access to the drain, but just didn't want to loose the flexibility).
I would think it would depend on the species of fish you plan to keep in them, many killifish and livebearers should do just fine along with others tolerant of very warm temps but I too think putting them in ground (even partially) would allow you to use them for a much wider range of species.