Just picked this up!

[drm315]

You have Java fern and Anubias rhizomes buried. They will rot. The rhizome must be above the surface. Usually they are mounted on wood or rock to insure they are not buried.

Oh man...I knew that about anubias, but not about the java fern. I have two java ferns in my big tank right now that I buried. How can I weigh them down without burying them? I currently don't have any appropriate rocks I could use.

 

[TMaier]

You are better off letting them float until you have a solution. Rocks or wood are the only things I have used.