Towns, I want to make sure you understand what I was trying to explain. The way you stated you did 10% water changes every three days (like it was enough) makes me wonder.
Doing a small water change obviously does not dilute as much as a larger. But let me explain further.
Doing a small water change very frequently does not necessarily dilute as much as one large water change. (i.e. three 10% water changes in a week does not equivilate to a 30% water change in a week)
Here is the skinny. Larger water changes allow you more time in one evolution to remove more crud (poop, decay, detritus, etc...). This does actually make a bit of difference if you spend your time siphoning trying to maximize the amount of this stuff you remove. This, in my opinion, makes them logically slightly more effecient in that during the days between your small water changes you build up stuff that again needs to be removed... therefore you don't have as much time to get the stuff you left last time (because your waste bucket filled up and you had to stop, or you reached the mark on your tank that lets you know you reached your stopping point)
Think of it like this. I have a dog, he sheds. For whatever reason, it has built up to a level that I no longer want. If I limit myself to 10 min of vacuuming every three days, I would never get the majority of his hair on the floor in one 10 min period. Three days later, I would have ten minutes, but if I start in the same location as before I would actually have to vacuum up the new stuff before I could get to the old stuff I missed last time. Effectively giving me a little less than 10 min to continue where I left off. Get the picture? Now, if I just give myself 30 min to begin with I can get just about all the hair. Next time around, as long as I keep up a good maintenance practice and don't wait too long between vacuums and don't limit myself to only vacuuming a portion of the floor at a time, I should even be able to get the entire floor in less than the 30 min it took me last time.
You need to find out what time you need to give yourself to get all the hair off the floor. Metaphorically, of course.
Also, your disolved organics or phosphate or whatever your nutrient is that is growing this stuff is not reduced as much in one water change when you do a small one. It also builds back up between the times you do them. Its basically the same "dog hair" principle. You are not going to lower these nutrients as fast with frequent small water changes as you will with doing the equal percentage in one shot.
I doubt your snail was the end cause. I have never seen a tank with hair algae issues that didn't have a corresponding nutrient issue.
So, why does this tank have a nutrient issue when your others dont? It could be tank over loading, your refugium is too small (you need a larger field of macro algae), you have mechanical filtration that is not getting cleaned or changed often enough, your water source is bad (though this would most likely show in other tanks and not be isolated assuming you are using the same water for all tanks), you are not providing enough good nutrients for the macro algae to thrive (iron, iodine), your live rock had large amounts of debris and dead organisms down deep inside of it that has just been leaching out organics (this is what TX is recommending you remove with his/her "cooking" technique) over time, a combination of more than one of these... I could go on.
Whatever your underlying problem is (which I DO encourage you to try to find out) water changes is an answer to remove the symptom (algae). If you feel you had to, I would not hesitate to do a complete water change. Just take care to re acclimate your livestock and do not allow your sand/gravel and rock to dry out (or your bacteria will die and you will recycle the tank). Do your best to ensure you get your new water close to the old in all the appropriate parameters if not exact and acclimate the livestock as if they were brand new. Due to some risks from increased stress, possible loss of your "attatched to rock" corals, zoos, etc. I would not do this as a first choice. It depends on how bad your algae is to you and if its growth is hurting your livestock.
Longwinded, I know, but I tend to drive home my points (or beat a dead horse, depending on your viewpoint
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