I have a 10 Gal reef and I just upgraded my lights to the Current LEDs with remote control. I think Amazon has the 20" (smallest size) for about $120. It's the cheapest I have seen for corals and you can adjust whatever you want on the blue and white.
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Current Orbit Marine LED Light, 18-Inches to 24-Inches is the product description on Amazon. I had the price wrong. It's $179 for regular price or $108 if you have a Prime membership. Maybe this link works. http://smile.amazon.com/Current-Orbit-Marine-18-Inches-24-Inches/dp/B00GFTK7CQ/