Examples of pressure-temperature profiles for planets in our Solar System and galaxy. If the planet mass is dominated by an ocean (infinite reservoir) with a low-mass hydrogen envelope, convection will be inhibited in the shaded region, due to water in the blue region and silicates in the red region. While the red region uses the ideal gas approximation, the blue region extends into higher pressure regimes; we use a color gradient and question mark to emphasize the behavioral uncertainty under these conditions. Data for Uranus are extrapolated from Lindal et al. (1987), the lupiter model is from Hubbard & Militzer (2016), and the Kepler 36c model shortly after isolation from Bodenheimer et al. (2018). Colored points correspond to the same symbols from Figs. 2 and 3, with added yellow square points corresponding to data from Bali et al. (2013).