jungle val melting?

Jungle Vals like harder water, so it might be that your water is really soft. Also if the tips were trimmed that can cause melting in Vals (though if they are really happy thay can manage it). On an aside note, I really would not recommend planting Jungle Vals in a 10 gal, maybe corkscrews would be better. I finally pulled and sold off mine from a 29 after they grew to the surface, grew along the surface to the opposite side and then curled back again, and started multiplying like mad. They were at least five feet long, and looked like they could have kept growing along merrily if I had let them.

Also, what are you doing for ferts and CO2?