Questioning my tanks health from algae

[ferro]

I have had my tank for a year now and things have been stable where they are at for the last 6 months. I have had a problem with film algae (maybe Dino's) and no Coraline growth.

My hermit shells show what grows on all my rocks and glass. Gives everything a brown/green look that I'm not fond of. My phosphates have not registered in 6 months as well as nitrates. I grow hair algae in my sump for nutrient export and have a protein skimmer.
It is an 80 gallon tank with a 20 gallon sump.
1.026 sg
8.1ph
8.5dkh
410 ppm cal
0 phosphates
0 nitrates

This is my tank without cleaning the glass for 4 days.
Any help or suggestions would be great!

 

[hyla84]

I had your same problem in my tank since a week ago.
My problem was your same sand, try to move it a bit and see if the water becomes borwn. If that's the case ths problem is the sand on my opinion.
But wait for other people as well