How new is the tank? If it's new (under 6 months), most SW tanks go through several algae cycles and most will just recede as the tank sorts itself out.
Are you using RODI water?
In my personal experience, I have found that algae on the sand bed resolves itself over time. Both cyano (usually maroon, always slimy and loosely attached - and not an algae but actually bacteria) as well as actual algae did a bloom on new sand, and then receded.
I had a heck of a time with cyano when I took my well-used but also abused LR, and upgraded tanks to include reef strength lighting - had it wicked bad for about 3 months, and then it just all petered out and then there was no trace of it. I think my LR was leaching all sorts of junk back out and feeding that lovely mess.
I usually hand-pick anything that is removable. And scrape the glass as needed. But a little algae is normal so I don't get all distraught about seeing it in my tank.
I haven't ever put any chemical in to treat algae in my reef tank. The only thing I've ever treated the whole tank with is a dewormer at one point. Make sure to be very confident in any chemical you put in a reef tank, especially a nano reef tank. Things can go bad very quickly in a small water volume. And inverts are a whole lot more sensitive to many chemicals than fish. Chemicals can also be absorbed into your LR / sand.