Well, I have had my VFTs for about 2 weeks now. I put them in an aquarium and everything looked great until about 4 days ago. I started seeing a leaf on one plant turning black, it was against the soil. Now I have several leaves on both plants turning black. It seems only to be leaves that are at the bottom of the plant, by the soil. Any ideas. I make sure they get good air circulation too. I am going to clip off the black leaves, ensure lots of sunlight and water....and ??