just to add..growth is stunned, tips are pointed down, tips are burning..all cal def..but i dunno
Try giving it nothing but water ''and only when its dry and the pot is light''
When you do have to water it put water in a spare bucket that your pot will also fit into, pour about 1ltr of water into the bucket and sit your pot plant in the bucket, your plant will draw up from the bucket what she needs to drink, after about 5/7 mins take her out and sit her as far from the bulb of your light as you can, ''making her work to the light''
have a very good look round for bugs, even at the top of the soil, it could be something just in that one pot ''in your soil eating away''
Hope that helps.