Scarlet Reef hermits definitely helped, but so did time. The brown came and went, as did the red and green. (Well, maybe not the green...
) But yes, in time all these phases will go their course if you keep up maintenance, water changes, skimming, etc. People quote the 6-month guideline often because it almost is universal.
But I'm sure you could have a bunch more Scarlets. They do an excellent job IME. Oh, and a whole bunch of assorted snails too.
Cheers,
Aj