In my 20g I have a whole corner of corkscrew vals that started out as 6 and is now a full thick bunch of almost 20. I noticed today that almost half of them rotted out. I've changed nothing. The thing is it seemed to happen over night. The only thing I can think of is they got too full and not enough light was getting down to some of the leaves. But still that isn't likely. Does any body know what the requirements are for that plant, Maybe I need to increase certain ferts.