The OP has inspired me, I went down the street and got a pack of the "hardy Aponogeton". I think there are about 6 bulbs in there. For 3.50 this will be some cheap thrills. Most of them floated at first, but this brought me back to my youth, where the secret was, the wipe away any surface bubbles, and if there is an air pocket in the bulb(soft spot) squeeze it underwater to force out the air. They all promptly sank, and hopefully in a few weeks I'll have some sprouts!
P.S. I love how some people are still commenting on light bulbs from walmart! Read the threads people!!!!