I've not had any luck keeping tuxedo urchins alive for any length of time - a couple months at most. However, I've got a longspine that has *completely* eliminated the GHA from my tank.
The problem is, he doesn't limit his diet to algae. He also munches on my plating montipora and blue sympodium. So far it grows fast enough to recover once he moves on to another area, so I've let him stay. But once he starts killing things off completely, he may find himself in the sump.