Anubias turning yellow and brown. What's wrong?

[Secter]

I planted some anubias about 2 weeks ago in my 75 gallon tank with a 48" Finnex Planet+ LED. I am also dosing Seachem Flourish twice a week and Seachem Flourish Excel daily (no injected CO2). However, the leaves keep turning more and more yellow. Now, the tip of the leaves seems to be turning brown and deteriorating. Lights are only on about 8 hours a day. I have the plants tied to rocks that are sitting on top of the substrate. The rhizome and roots are not buried.

This is my first attempt at live plants. What am I doing wrong or need to do?

 

[zer0signal]

Iron, Potassium, Magnesium? I am no expert yet, but it might need those in the water column. You can use API Leave Zone (Iron and Potassium) to get that in the water.

I am sure Veterans on here can correct me or confirm.

Handy chart for possible issues with plants:

http://www.verdanttriangle.com/wp-content/uploads/2014/03/def-chart.jpg