It is a complete 100% misnomer that nutrient control, adding or subtracting, is the key to controlling algae. Its one of ten possible ways to work algae as we need it worked, its my opinion that not starting off with parameter detailing is the right mode and instead do the total opposite move that led up to the invasion: detail rasping and cleaning of the invasion, with cheats as permitted, to forcefully take back ground with no wait. a literal opposite move is quite powerful, so I feel its the initial go to best recommended because it will never bleach anyones coral to scrape algae off surfaces.
it will never harm an invaded reef tank to take the sandbed that clouds if you reach in and grab sand w pumps on, and turn that into bare clean grains of sand via powerful rinsing within an hour or four depending on size, and storage. cloudless/no algae fuel, and no reason to have to offset stored pockets of phosphate and nitrate now.
consider opposites to the traditional algae controls... study opposites is my advice to new readers if you want to avoid waiting and if you want your first reef to work, the first time you try. You have to make that occur, not hope.
algae control is one zone of reefing you don't have to take slow.
no doubt, many options including nutrient controls might and can correct that in time...but what applying those to the clean restored condition tank, to prevent recurrence? vs waiting for them to hopefully stop growth, then cause mass dieoff, then wait for the mass to degrade...consider an opposite ordering of the common steps. a fell swoop take back ground move. the complete opposite to how the tank got invaded is how to uninvade it
having lucky grazers never hurts/ but that's depending on animals to hopefully work, always take action which you've certainly started for sure, well done.
update pics
all of reefing is built on taking whatever the rocks throw at you, slowly, and hoping for a win.
In your case, two squirts of peroxide on the cleaned surfaces after you scrubbed them w stop this growback, its a cheat, and a quick one too.
when coralline and coral take over, you can have higher nutrients, and still be algae free, within reason.
I run hundreds of nano and pico reefs online this way.
*that's not to say that changing nutrient stasis doesn't kill algae, it does, hence gfo popularity. but it also stresses corals who do fine in ranging conditions, and hate to be stripped of particulars, we also see with GFO and similar actions when overdone.
grazing is how nature does it, not nutrient control.
someone take hobby test kits to Fiji, not wrecked by algae, and you'll test clean waters. Yet millions of grazers have something to feed on
*aquarists are trained to think algae is bad, it finds its niche just like corals do.
the reason there are fifty opinions on what controls algae best, is because all 50 have worked for the people offering them, they're legit offers.
sandbed cleaning / awesome, that's the best nutrient controller we can use and still be totally safe within the tank.
This attack method above doesn't have to be the go-to for every single invasion, but 98% of reefers have never ran it once. learn it powerfully, have it as a tool already practiced and then try hands off/less work methods like stuff you add to the water. the number one reason people wont even consider opting out of an invasion at the start, on day two, vs catchup, is because they are concerned about instability in the cleaning process.
threads exist to eliminate the concern, with lots of people documenting their resets.