I agree with hank if you can cut down the nitrates along with phosphates you will see a difference . I had a big out break of green hair in my predator tank , mine was full blown you couldn't see any rock
I did a 50% water change than another the next day , after testing I still had nitrates and phosphate . did another 50% water change
they were now readable with testing . the following day I got the same reading ,
so I did one more 50% water change ,
it took 4 water changes to get things back to normal;
Now for the fun part , I mixed 4 buckets of water and 1 fresh water bucket.
first bucket was saltwater for scrubbing off all the hair from each rock , second was for 1st rinse , now the freshwater bucket mixed with peroxide 30sec dip , now back to bucket 3 another rinse , bucket 4 was to hold all rock till I was done ,
this took me almost 3 hrs , added a bottle of Dr Tim s bacteria just to be safe , haven't seen hair since