wabisabi, If your bullosa plant hasn't gotten any better, try this. It has worked very well for me with all my emersed crypts when they start to go downhill (beckettii, cordata, crispatula-flaccidifolia, longicauda, and minima). I don't have bullosa, but it might work for that one too.
Soak dead tree leaves in water for about two weeks. Put your plant in its pot in an aquarium or any kind of container that lets light in and can be covered to keep the humidity high and fill with water until there is about 1/4 to 1/2 inch of water over the substrate surface of the pot. If the plant is not rooted weigh the rhizome down on the surface with a pebble. Rinse the tree leaves, break them up or cut them up with a knife and put them in the water. You want a lot of these soaked leaves in the water, but don't add a huge bunch all at once. I don't think it matters what kind of tree leaves you use, but I use oak leaves just because they are thicker and more substantial than many other leaves and should last a long time. When my crypts stop responding to nutrients and start to die back, adding the leaves perks them up quite quickly. I suspect the leaves have something to do with making iron more available, and they also may provide a steady source of CO2. Neil Jacobsen has an article about how he discovered that leaf mould (partially decayed leaves) improved the growth of his crypts tremendously. Jacobsen, 1992
. He recommended beech leaf mould, and, because of that, everyone started using beech tree leaf mold. I don't think that it has to be beech leaves, probably any other dead, soaked and partially decayed leaves would do. The leaves have had a very beneficial effect on my longicauda and minima, and they have produced runners and many new plants.