Tuxedo urchin Advice

[mike31154]

I've had a lone blue tux urchin in my mixed reef tank for years. 3 VorTech MP40WES, no mishap so far. Occasionally after lights out, I have the odd snail that crawls on to the VorTechs. Just last night I heard a rumbling sound from the tank, shot a flashlight beam at the powerhead & there was a snail part way into the front of the cage. It figured out on it's own that it should retreat before I had to intervene.