If it's Byprosis, you will never get rid of it with snails or any other animal. I am battling it right now. I am in the process of try the Tech-M solution.
If you can pick up the rock by it, it's likely bryopsis. Sea hares do work, but then eat themselves out of a job Some may be available in a few weeks in Sarnia
No snails or fish that I know of eat true bryopsis (hair algae) with results. You can get a small patch that sticks around for months but if you keep it clean (turkey bast it) it has always gone away on it's own. To speed up the process I have used a tooth brush to get it off...but you can never get it all.
It's not hair Algee, phosphates are at 0. It's mossy looking, grows on power heads and one side wall that gets low flow The snails seem to be helping but it's only been a couple of days
hair algae can grow in clean water.....I did mention I have gotten it in the past right? I've had a thriving tank and has small patches of hair algae before. I mean if you have a tank full you probably have a water quality problem but a small patch here or there can happen in clean tanks.
The mossy part makes me think its hair algae. Do you have a picture?
i have a picture up in POTM in june but its hard to see, its not every big. looks more like turf algea. i get them on my power heads alot, to the point where im thinking about buying new ones lol
it almost looks like green coriline algee but with alittle mossy turf lol
its hard to explain and my camera can take up close pictures