The reason that the water sprite isn't making it in your tank is because your light is too low. Stem plants like water sprite generally require high light. I don't know what the wattage is on that 29G's bulb, but it's probably in the 20-30w range -- that is, less than one watt per gallon. Water sprite won't survive in that environment. I'd concentrate on easy-to-grow plants like anubias, java fern, java moss, and certain cryptocoryne species.
The fluorescent screw-in bulb in the MiniBow (I think I saw it was a MiniBow in your other thread) may grow water sprite, but it might not. That's your best bet, I think. It's going to be more of an experiment in that tank because the watts-per-gallon rule of thumb generally applies to normal fluorescent bulbs -- I don't know how it would scale to the screw-ins. The WPG rule breaks down in very small tanks anyway.
To put it simply -- no water sprite in that 29G, and in the 5G, maybe, but I wouldn't guarantee it