Gravel turning green

[drtrash]

Recently, something has shifted causing gravel to get green. Assuming algea. Tank is mature, no hair algea, some sprigs of bryopsis. Rarely do water changes but have done 20% in 2x in last month (100 gal tank), went black for 3 days, turned off t-5s and cut led to 30%. My guess is a chemistry issue or green is cyano not algea, not matted or hairy. Di cartridge is showing 0 on meter, but could be some micro element. Not sure on what to try next. Dropped feeding too 2x a week, low fish load

 

[BighohoReef]

What are your over all parameters? How mature is your tank? Do you have a picture?

 

[vetteguy53081]

Its algae and a few things can cause this:
- Excessive white lighting or intensity
- Nutrients high from feeding
- By any chance is tank at or near a window?

 

[drtrash]

Not near window, kessil led set at 18k color only at 30% intensity, was at 50% with 4 t-5's, chnaged lighting and only feed 2x per week for a month and no change, looks like dino but green