I have been using the Marineland Reef Capable LED light system for about six or so months on a fresh water planted system. I’m not sure how well it would grow corals but I would assume softies would grow okay with these lights. I like the light system over all but I would like to add another light fixture because completely coverage isn’t obtained with one of these fixtures in my 75 gallon aquarium. I think a 55 gallon would be fine with one light because of the smaller depth of the tank. I have the lights towards the back of the tank where the plants are so the front of the tank becomes a bit darker. I do love the shimmer the lights put off like metal halides do. Also these lights are very energy efficient and produce very little heat. I like the idea of not having to change bulbs every 6-8 months as well.
Pros: Low energy use, 54 watts! Low heat created by the lights which helps the tank temp to not rise. No need to change bulbs because they shift spectrum. Nice shimmer effect the same as metal halides produce.
Cons: Expensive technology. Need more than one unit to really light up a tank from front to back. The light switch has three settings, one for actinic only, one for off and one for both actinic and 10,000k. This removes the ability to have timers on the system to swich from off, to actinic, to full light and vice versa. This light system would not do well for a 60″ tank. It will fit because the legs extend out 6″ on either side but the tank would be dark on the sides compared to the middle.
Other thoughts: I will be much more impressed with these units once they get the cost down so they are more affordable. We are in the very beginning of LED light systems and I think with a few years of technology they will become brighter as well as more cost effective over all.