Maybe consider using a "tannish" (not sure if this is a real word) color paint for your background? I think that it gives more of a sense of depth than the usual blue/blacks, plus with any lighting over 10k, it tends to look fairly blue anyway. This is an awful example from my 120 Caribbean tank (just base LR when I took this one), but if you compare the color to the background in dive pictures, it's actually not too far off. Can be easily scraped off with a razor blade (provided that you can reach) if you don't like how it turns out.