Crypt Parva - easy/hard?

easy. i have it in my 10 with 2 cfl's very little ferts, no co2 or ferts. obviously not optimul growing conditions so they grow very, very slowly. but i've had them for over a year without any problems

Should be fine, just be aware that it grows extremely slow, even in high light/CO2 conditions.

Ditto what legomaniac said. It is very easy, but grows slowly underwater.

It's a nice algae magnet too if you have issues with algae.