What I did is,
Do weekly water changes and remove the algae with an airline pipe with a tube connected to it so you rip the algae of of the rocks and the water from the airline pipe will suck it into a bucket. (this will mess up your water parameters a bit, but it's worth it)
Get a better protein
skimmer (triple the ratings of your tank for example I'm using a 400 gal. skimmer on my 125.
Buy turbo snails and other clean up crews
Buy tangs and lawnmower blennies
Make or buy a refugim.
Buy more
live rock.
Good water circulation.
Make sure no direct sunlight hits your tank
I did all of the above and it took me a whole year to remove it. I just removed it once and for all last week. I couldn't see any now.
__________
get rid of them fast. The longer you wait the harder it becomes.
Notes:
-never let them die unless there is very little of them. When they die, they release their spores
-never scrub the rocks, they will release spore and nutrients
-don't depend to much on fishes to eat them (especially long ones)
Good luck with your tank,
hope you get rid of them once and for all.
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