Help???

Today i went and checked on my gurl. She looks like she is growing but the tips of her fan leaves are black? Help??
Im still new to growing and i was watering her every 3 days with a teaspoon of Mg and and teaspoon of Malasses in the water. I think this may have something to do with it.
Should i flush her outt?? or what. Im so worried ;(

flush with clean, pure, ph balanced water..... no more additives for a while. good luck

Thank you soo much!.

You don't want to add nutrients every watering