I have been using the reefbreeders
light 48" over my new 120 gallon (24x24x48) mixed reef tank for about 9 months now and love it. When I was planning my upgrade from a 65 gallon to the 120 gallon, I looked at the radions, hydras, vegas, etc and they were going to cost me $1500. I saw the reefbreeders at a club meeting one night and for $500 I was sold. No, it does not have the fancy computer and wifi interface or per channel controls. You don't need it. They are programmable and they do growth coral. My montipora was almost dead 9 months ago, it only had 3 dime size spots left, Now its about 6 inch by 10 inches and is growing spirals. I run them 12 hours a day ramping up to about 50% for 2 hours and back down. It think would work great on your 55gal, and give you growing options for a 75, 90, 120 or 150 high in the future, all 4 foot long tanks. The guy who runs reefbreeders was great to work with. Last my friend had the maxspect 160w 27 inch on has 4 foot long 75 gallon and just replaced them with the same light photon 48. His tank was not doing well even at 100% on the ravors. Its looking much better now.