the best option would be a separate tank that hold majority of water and have it circulate the water some minimum amount. power heads or stiring will do 5x the oxygenation. gasses dissolve almost instantly. a wave or vortex is a rolling mass of molecules constantly churning at surface ready to accept more o2, vs bubbles that before they even hit the surface have exhausted what o2 they can provide. the bubbles don't agitate the water as well as a powerhead either, so it'll stay cleaner longer with less maintenance required.
the powerheads for salt water aquariums that have full 180-degree articulation and a magnet base are the best options with any curved container.
otherwise, get something that distributes the bubbles all over (rings and such are better than the little cylinders), because the 2nd function is to stir/agitate. helps prevent micobial growth. use smaller volumes and change it out more frequently if you run into issues. obviously can't have a powerhead near roots, lol... would be funny to watch though.
you cna make your own for that matter. smaller bubbles probably do oxygenate a bit better but it won't make a difference. just drill some holes in some tubing and coil it around at bottom. black the end or bend it back and secure tight with zip tie. it really doesn't need to be fancy and you'll avoid buying those airstones every 2-3 years as they clog