Sounds like many of you have had great success with prolifs, too!
I usually keep the water just below/touching the bottom of the prolif. If some of you actually have the water level over the bottom of the prolif, then perhaps that is a better idea. I always worry about rotting the crown of the prolif. if water covers it.
As long as I remember to change the water often (typically every other day), I always get roots to grow. And once the roots are strong, I plant them in pots and have very good success growing them to maturity. I have not had any of my prolifs bloom yet, though. Probably this coming year I will see blooms on some of them.