corkskrew vals rotting for no reason

[FishyMatty]

In my 20g I have a whole corner of corkscrew vals that started out as 6 and is now a full thick bunch of almost 20. I noticed today that almost half of them rotted out. I've changed nothing. The thing is it seemed to happen over night. The only thing I can think of is they got too full and not enough light was getting down to some of the leaves. But still that isn't likely. Does any body know what the requirements are for that plant, Maybe I need to increase certain ferts.

[tanker]

My val grows out of control.

I do not think you can have so much that no light reaches the bottom. What kind of lights do you have, and how old is the bulbs?? I assume you change water, what do you add (ferts).

[FishyMatty]

I have 130w on a 20g they were growing out of control then all of a sudden they were rotted out. I dose Micro, macro and trace a long with co2.

[J double R]

thats kinda odd... btw ive never lost a plant youve given me, either.

[fishcatch22]

has there been any sudden change iin the water chemistry of any and all water that is in, goes out of,or enters the tank at any time?