No, I personally dont. Not if your params are good and you've tried everything else. My crocea is happy on the bottom of my 24" deep tank with my 250s a foot above the water. With them at 8" I had to keep my open brain under a ledge to keep it happy. Take a look at this pic for reference. 400 luminarcs http://www.reefs.org/phpBB2/viewtopic.p ... faux+built
thing is im bent on replacing my substrate, so everything comes out. I've put them in the tank for the night, or at least 3-4 hrs untill the sand storm in my display subsides.
wish me luck.
you gave good advice btw... but I was doin the substrate anyhow