Hornwart dying

I just reciently moved a few sprigs of hornwart to my 6g tank. It is bare bottomed due to cracks developing in the bottom of the tank. I have had major problems with ammonia due to our town now adding chlorimine(?) to the water. The horwart was/is taking over the 10g RCS tank, and I needed to thin it. Now in the 6g, it is loosing its leaves. I don't remember if this is normal for it due to a new environment, or is it really dying. I have not yet added ferts to this tank (has no shrimp in it). Any and all suggestions are very welcome!

Edit:

no substrate, lighting is 15W (10,000K), Tap water contains up to .50ppm of ammonia, no Nitrites, Nitrates are at 10ppm, HOB filter