I don't see the cyano, but do see diatoms on the sand, maybe the Rock. I see small patch of GHA.
I would not continue using Phosban if phosohate tests lower than 0.03, especially if their are any corals in your DT
It's hard to read for me on this device, but looks like 16 hrs total on a ramp.
If I read that right, I was thinking too long, but that's just in comparison to mine, 30 minute ramping both ends, 8 hours at full intensity, 1 hour moon, then black for 14.
Algae will not survive forever when deprived of its three foods, light, phosphates, and nitrate, but, to a lesser extent.
I would give a good scrub, 4 day blackout followed by winding back the light photoperiod, slowly, until it's maybe half (if you can turn down reds, greens, yellows, to say 10%)
Measure and keep nitrates consistently between 2-5ppm. If higher, consider carbon dosing, that, over a month or two, can drop nitrate by easily up to 40ppm.
Measure and keep phosphates consistently between 0.03-0.07ppm, if higher consider using an LC process or GFO. If you have corals, never go ZERO, they starve.
Algae will go from dark green to lighter beige as it dies Continue to scrub of nutrients off Rock and remove manually with a water change and through skimming.
For diatoms, little can be done, it's just time with them. They feed on silicates in the water and once silicates reduce, diatoms seem to fade as well. Unless you have a sponge which also feeds on silicates to build its structure, so they go away much faster. Keep the flow on those areas.
Keep up flow with lots of good random flow, try to Not to have any dead spots in terms of flow.
It's takes about 6-12 months AFTER those parameters are stabilized, to be algae free (in my case)
At one point, it will just disappear (in my tank it took 1 year). My N and P have been locked in for 27 months now, still no algae returned (except coralline), with a Weekly 10% water change, light feeding schedule. I cranked up the lighting. Still nothing.
This is the process I used to eliminate my "uglies" stage.
It was the least fun stage of reef keeping, can't get around it, but you can mitigate it's hold.