low light crypts

There are very few Crytocorynes that are anything but low light plants.
Expect the unexpected. They are funky plants that will sometimes melt for no reason, but that's not the norm. If you keep a pretty stable tank, they should all do well for you.
For a background Crypt. I suggest you try C. Balansae. They are slow growing, but really nice when they grow in. C. Wendtii
is very dependable.
They all love extra Fe and it doesn't have to be added to the substrate. You can dose it right into the water table for good results.

Len

C. spiralis is less light demanding and grows faster than C balansae. They have long thin leaves with a smooth texture instead of the puckered texture of the balansae.

Agree w/Robert H on C. spiralis and C. balansae, but the C. balansae is sooo much more impressive and taller it is worth the extra time. Both are well worth growing.