I have one for you about black stuff on my adelae. I recently took my mother "clump" and seperated it out. In the process I found two little plantlets. One I gave to my finance and hers is doing great. Well on one of the adult plants and my plantlet the leaves are coming up with what looks like a hard black crust that flakes off, but the leaf dies. The majority of my adelae looks great, well the ones sitting in it origional pot and the origional windowsill. The one that is giving me this problem is on a different windowsill, yet it faces the same direction as the origional.
I grow in 50/50 peat perlite in very wet conditions.
Tropical Fish Enthusiast
Remove that which is black. I've been growing mine such that I let the water evaporate to almost gone, before filling it up again. Not sure if that would solve the problem, but this is what I do. Correlation need not be causality!