I think I finally solved a problem that has plagued me for years. I can get Water Sprite to grow well if it is rooted in soil and has aerial leaves. This is a perfect combination for maximal plant growth. Works great in a small tank that is 12 inches high. However, 55 gal tanks, which I like, are 22 inches high.
Before I set up my new 55 gal, I glued (epoxy) plexiglass supports for glass shelves. With the shelves, I can put containers with soil for Water Sprite. I've also added lava rocks with attached Java Fern.
This is similar to what the pond people do-- incorporate shallow areas in their ponds for emergent plants. In the past, I've stacked bricks to bring my Water Sprite closer to the water surface. The glass shelves are much better.