As a temporary measure you could cut down your lighting hours to 6 to 8 hours a day, or perhaps reduce the intensity of the lighting, if the unit is dimmable. But you need to work on Nitrate and Phosphate issues, perhaps need more flow in your tank? It could be overfeeding or perhaps just bad live rock. We'll need to know a lot more about your system, your parameters, your feeding and water change regimes, what are you dosing, filtration, skimmer etc. photo's would help too.
Those rocks got so much nutrients within them.
Next time you do a water change. Put some old water in 2 open tubs. Rinse and scrub the rocks in the first tub. Use a toothbrush. Take it out of the water and let it drain, Repeat this process a few times trying to dislodge as much of the crap as possible. Final rinse in second tub to get rid of algae spores. This will help speed up the process of getting the rocks in a better shape.
My parameters are
I have kalk that i mix with my ato. I have 1 x 2500lph and 3500lph flow pumps . Return pump is 3000lph .
Skimmer is bm curve 5 .
In my sump i have a filter sock that i clean once a week sometimes twice. A internal filter with matrix . Compartment with liverock,then my return chamber with 2 filter bags of carbon.
I feed twice a day roughly 10 pellets and every 2nd or 3rd day frozen food but if i feed frozen food i feed once a day.
That was a pic when i started my tank the first week , just to give you an idea what is in my sump .
I top up with ro water .
I noticed my one flow pump wasn't working this morning , cleaned it out , now there is more water movement in my tank . I do a 20% wc every 2nd week and 1 50% once a month .
You say your nitrate is zero, what is your phosphate? My tank likes to get a bit of cyno when I have zero Nitrate but high levels of Phosphate. As soon as the Nitrate and Phosphate levels are more in sync with each other it goes away.
Looking at your algae you can pretty much bet your Phosphate is not zero?