I do not want to sound too critical, but I likely will. Doing the comparison using two different systems will not work. I have an ongoing comparison in the same system. Two display tanks, same sump (so same water parameters). Radion gen 3 on one display tank, and ATI T5s on the other, and a few duplicated corals in both tanks. But, even in a situation like this is very hard to reach conclusions. Two many variables: coral placement, PAR reading comparison (comparing readings of LEDs and T5s is not straight forward), water flow, different clean up crew, neighbor corals are different... Even in the same tank, is not infrequent that same corals with different placement look very different in colors (and grow differently too).
The comparison gets more complicated when trying to access the ability of those lights to support health of different types of corals including different SPS, LPS and soft corals. Impressions are biased, even more with time as we naturally select what corals are thriving in our tanks. We kill some, and some thrive and after a while, we only have thriving corals in our systems and conclude that the system make corals thrive (forgetting that it also kills corals). Some people that will not accept not being able to keep a certain type of coral and keep trying, know what I am talking about. I bought online rouge mili frags twice from the same vendor and both died within weeks. All other corals thrived and I have several milies growing well, but for some reason could not keep rouge millie twice. It might be a coral incompatibility with my water conditions, my light conditions, my dipping procedures, or that this vendor's rouge mili was not doing well to begin with (it is so hard to put a finger on what is the problem sometimes). My point is, I will buy it again from another vendor, but at this point I know my system works great and grow corals well, but not all corals.
Any ways, just a few mildly haphazard thoughts...
CB
