As far as I know flourish is the only thing that melts them.But since you said you do not use it,I wouldn't worry about it.If you decide to start using it,start with less than 1/2 dose,do that for a week and dose a little more week after week.I still do not fully dose my tank with it because of the val.Alright well it sounds like it shouldn't be too hard of a plant to keep. It must be the corkscrew val, haha LFS and their common names.
So, even if they get melted they grow back? Thats good to know.
Thanks everyone. I think I am going to have to make a trip to go and get some.