mythicality wrote:
I recently added a fermentation type CO2 system to my 25 gallon planted tank
which also has grow lights on it. At the same time I started supplementing
with iron. Most of my plants are growing like crazy with the new
conditions, but some of my crypts are melting. A friend mentioned that they
will likely adjust to the changes, and then send up new more adapted leaves
from their roots. Does this sound true?

Crypts are notorious for melting when conditions change on them. I like to
call it the "ack, you looked at me funny! I'm melting now" reaction, heh.
As long as the root stock/rhizome is healthy, the plant will grow again as
your friend said. How long it'll take is variable. I've had some bounce
back to big leafy plants in a few weeks and others stay small for months.
The small ones are usually younger, smaller plants to begin with though,
so that has something to do with it, heh.