Look at the experience level of the person giving advice, and look at their tank specs in their sig line.
THe actual answer is, fish swim in very powerful currents in the ocean, so while I don't know koralias by experience, I'd say you're probably ok as long as your sand will stay put. "Walking" sand is a serious problem and will destroy corals and irritate gills. Strong current is a standard bit of advice for people keeping coral, particularly sps corals.
I use Sea Swirls to 'sweep' the current through my tank, and I use a T joint as a nozzle to keep my sand still and to avoid blowing my fish backward.
Every tank is different in config, so you will only be able to fine-tune the situation after you have your tank up and running.
What kind of tank are you after? FOWLR? Reef?
And re your photo problem: use Photobucket.com---it's very Reef Central friendly.
To insert photo, post, then Edit Post, and [with the url of your photo in your clipboard] hit the IMG toggle: a blank will appear, and you drop your url into the blank, hit the confirmation button, and the appropriately sized photo will turn up large at the foot of your file.