It wasn't until I started reading this forum that I heard of people not using mechanical filters. The LFS
who I went to for advice before getting a tank had me convinced I needed "everything" which was why I ended up buying second and instead of from them...too expensive!
Even if I only have about 50 lbs of live rock to start with in the 125, I wouldn't need the cannister filter? The three stars are a Brittle Star, Serpant Star, and a sand sifting star? I think...look like a sandy color "normal" star that spends its days on or in the sand. Been feeding algae sheets because of the tang so I'm assuming the stars are taking care of whatever the tang doesn't eat.
Melosu - The tank currently is not drilled but that would be the plan. Somewhere on this site there was a link to a company that sells the kits to drill the back and put in the overflow. I was planning on going that route so I could put in a refugium.