They either do well in tanks, or do poorly. There seems to be no middle ground with them for some reason.
They do very well in my tank, but horribly in 2 out of 3 lfs I frequent.
Current levels can be anywhere from light to strong. Most hobbiest seem to like strong, but they do great in either.
Medium to strong lighting.
I hear that iodine is important to their growth, but if you are feeding your tank anything, odds are that is enough iodine for them (in the food).
When they start doing well, they will "grow like weeds".
Good luck,
kris