Are those pics pre-fluc dose or post-fluc dose? I guess it doesn't quite matter since you've already started the regimen. At this point, I'd say continue with the fluc dosing regimen, but try to manually remove as much algae as you can.
I think there's a see-saw thing going on between algae and corals for the nutrients. I'm no expert, but my guess is right now is you have very high nutrients, and most of your nutrients are being consumed by the algae because there's so much of it everywhere- the balance is well in its favor and it will out compete your corals. To shift the balance you need to manually remove it (thereby exporting nutrients), less algae means less of it to uptake your nutrients. You probably will still get a lot algae growth because even though your tests are zero or ultra low, it's still there and the algae is very efficient (hence why people use it to export nutrients).
Only after a time when the nutrients come down to beneficial/healthy levels (through export), will the algae slow down. it will still out compete corals, but less algae means more nutrients will be available to the corals, and eventually the balance will shift in favor of the corals (or you can put your thumb on the scale with other stuff like carbon dosing, gfo, algae scrubber, skimmer, etc).
About a year ago, my tank looked like yours but worse. every surface (glass and rock) was covered in hair algae and bits of bubble algae. I almost shut my tank down it was so depressing. My NO3 was over 100 (salifert was dark pink, so maybe more than that!). My PO4 was 1.7 (!!). But about 7 months ago I decided to try to revive my tank and bring it back. I did 20% water changes 2x/mos., every water change I scraped the glass and toothbrush scrubbed the rocks to remove algae, started carbon dosing (diy NoPox) at half dose and building up gradually (I have stopped it now), cleaned my skimmer every few days, tested NO3, PO4, and alk every day, dosed AFR at half dose building up to about 10ml/day, made sure my RODI was zero tds, automated my lighting, added slightly to my bioload, added an urchin and a bunch of emerald crabs and a few hermits (and snails which all died w/in a few weeks...so my current CUC is one urchin and a few hermit crabs).
Now, at this point about 7-8 mos later, I still have a few patches of hair algae on the rocks and sand, but nothing like it was. It is night and day. Now my NO3 is at 2.5-5, and my PO4 stays between .13-.23. I have an algae scrubber but have not installed it yet, but hopefully soon to get those last stubborn patches. I bought fluc, but never used it. It's a process you have to be committed to. That's why I say stay committed for now to the fluc regimen. If things haven't improved at the end of it, do something else, but don't quit a 1/3 of the way into it bc you're not seeing what you want.
If I can do this, so can you. Good luck!