I'm glad somebody posted something about crypts. Bought three of them a couple months ago to stick in my son's 20L. Have read that they were rather low tech and easy to keep, so decided to grab a few from the LFS.
Stuck them in regular inert gravel, gave each their own Flourish tab - no CO2 other than what the fish provide and the light is stock 8000K - great results with strong leaves, excellent growth and a few baby leaves poking their way through since then.
I love my other low maintenance moss, fern and swords...but sometimes they can be a hassle - black algae, sporadic growth, ect. But, if these crypts become almost maintenance free except from a tiny bit of pruning in the 20L, I just might consider going all crypt and calling it a day!
The longer I'm involved in this hobby the more & more I'm convinced that Bio-Type species tanks are the way to go. Plants and fish/inverts live together in nature for a reason. I find the less I try to fight nature the better my tanks look.
- DogFish 1.24.12