dying vallisneria

Hi all, I’ve planted some Vallisneria Asiaticia “Corkscrew” in my aquarium and it’s suddenly all melted. I know, like Crypts, Vals are prone to melting in a new aquarium, but it was doing ok for about 3 weeks and then every single leaf melted (the attached photo was taken on 28th August)...

I have a Juwel Rio 125 litre (T5 lighting, I think; def not LED), “pimped” internal Jewel filter with 2kg of biogravel. Sand substrate over Tropica aquarium soil. . pH 7 - 7.5. Tap water source is hard (London) - DH14. Amonia, nitrate and nitrite levels all fine. Pond snails. No fish yet. The...

About 2 weeks ago I got some Jungle Vallisneria from Petco and about 2 days later the leaves started to split and one of the leaves is rotting and turning transparent by the crown. The roots seem brown but large and the crown is above substrate which is seachem flourite. I dose flourish, excel...