Possible cause for white tips and slight stn

[Jake_the_reefer]

Hey guys I just noticed in my nano reef that the new branches coming off my acros are very pale and one acro appears to be having some slight stn. I want to jump onto the issue before it is worse.
I reduced feeding due to a cyano issue and now I think that is what is causing issues with my acropora.

My parameters as of right now are
Salinity 1.026
Temp 76
Alk 7.4
Calcium 420
Nitrates less than maybe .5ppm could be lower. Barley visible looking at the salifert test in low range view.
Phos .03
Mg 1230

Attached are some photos. I may be seeing nothing. Better safe than sorry

 

[Justfebreezeit]

Mag pretty low, not sure if thats it though

 

[reefpeeper]

Maybe nutrients too low

 

[Jake_the_reefer]

Maybe nutrients too low

That's my thought

 

[reefpanda]

Going with nutrients as well

 

[Jake_the_reefer]

Going with nutrients as well

Aight. I'll slowly increase nitrates over the next couple weeks