the reason we should physically remove algae the second it pops up, and not change params, is to find out if a controllable strain has set in.
algae grows in great params, on a real reef, so its not always params causing the issue.
the cause of most gha problems, not the minority of problems, is nongrazing
there is likely a clean up crew in there, but they're not matched to the target and aren't working so the target was allowed to spread.
by commanding the first win, we know if it grows back rampant this strain isn't to be toyed with, potential reef killer
if after the first removal it stays gone a good long while, then if it comes up again you know you have more room to be hands off.
be sure and look at the first few pages of the nuisance algae forum, its very rare to have anyone asking for help with a cleaned tank, needing regrowth prevention help, because they stay busy making it algae free but want to work less (universal cure to all invasions in reefing, simple will)
whats common is us allowing 100% invasion, then posting for an ID, then ordering a scope off
amazon, then confirming the id, then testing params, then dosing for a param= 100% hands off caused about 90% of those invasion challenges.
we need more hands on in the hobby to avoid total wasting, loss/start overs.
purposefully invading one's tank as an 'uglies' allowed phase is a very bad choice / our hobby circulates methods that welcome invasion challenges
To form an accurate opinion on how algae invasion works, don't look to our own tanks, u might be lucky
Go set up help threads in the nuisance forum and see what it takes to earn fixes/opinion earned.