Yes it's normal. Scuba divers see algae+corals in the best waters in the world. Grazing keeps it in control in nature, not nutrient starving like aquarists use
This is a neat way to see the matter in my opinion:
Not one time is algae growth permitted in the tank destined to be in control. Hardly anyone ascribes to that mode, the result is tanks in droves who never escape new tank syndrome we can see in threads across forums. Algae problems more often than not due to the old methods.
Purposefully farming that new algae seeds the tank with fragments
When the new algae happens to be an invasive hitchhiker, the practice of hoping maturity drives it away seeds the tank with bryopsis or gha whereas simple early hand guiding would have changed the destiny of all wrecked tanks we can search out
Nts algae means we are hand guiding more often, and when the tank matures we don't work as much. No tank can be lost in this method, and thousands are lost annually by the standard method
All it takes to keep the wheel going are awesome established tanks prescribing the hands-off method where there tank happens to self-guide back into compliance, then new tankers think if they wait longer it'll just go away, and won't for the masses.
Of course nutrients in check, clean up crews, algae eating fish, various filters.... All valid and successful. But we see those as the preventatives of algae, and not ever the remover. Merely aligning the tank in that order of prevention vs removal being two different actions makes all our nano reefs run algae free, no reason a large tank couldn't join right in.
The number one method to gain perspective on algae in the reef tank isn't to prescribe online what made our own tanks algae free. It's to start up a thread inviting a hundred challenge tanks live time and try different methods to cure them, that will change anyone's perspective on algae in the reef tank.
This is how I prevent algae on my new corals, day one or day 3000 in same tank:
http://reef2reef.com/threads/5-new-...be-cured-using-a-rasp-and-a-test-rock.257862/
