Plant Not Healthy? Burning look?

[reavery]

Hi All,

Please help me, as im not sure what is going on to my HC!

My tank spec:

1. 24W x 4 T5HO lighting (Used for about 7 to 8 month)
2. EHeim 2215
3. Ada Aficana
4. 2 ft tank (24inches x 15inches x 15inches)
5. Only HC is in my tank, no other plant!

This tank aged is about 4 month old..

It look like a burning look.. is that an algae ? hmm, it just appear recently actually, happen about 2 to 3 weeks times... and i just got oily surface appear in my tank last week .

Did wash the filter..

im dosing EI , if i overdose , will it cause this kind of plant burning problem? hmm.. or it is an brown algae?