What size tank and what lighting do you have? Water sprite is very easy to grow but will suck up all the nutrients in the water quickly so you will need to add something like Seachems Flourish Comprehensive weekly after your WC
. Water Lettuce needs room between the light and water. They need an open top tank to grow properly. They will also cover the surface of the tank not allowing light to penetrate down in the water. IMO
your best bet is to do Water sprite.