Ooo, I really like the dimensions of your tank! Fun to play with rockwork in there!
One thing I notice is that you are using a power filter with biowheels in it. I would suggest you remove the biowheels as they are designed for fw tanks, and will become nitrate factories which is fine in fw tanks, but not good in sw tanks! If you just remove the wheel part the rest of the filter is ok provided you replace the filter media at least once a week. Oh, and the Long Spine Urchin will outgrow your tank as well. Too bad though, I really like them too!
