<a href=showthread.php?s=&postid=14879972#post14879972 target=_blank>Originally posted</a> by jbird69
I am running a 400w radium mh bulb on my 50g, I also have two 39w t6 that I run for some added color and dwan/dusk. With all that wattage burning inside a wood canopy, my temp swings less than one degree day to night. All I have is one 3" computer fan blowing across the water of the dt, and one blowing on my ballast underneath. (interesting, I was getting a 2 degree swing before I added the ballast fan) And even if you do get temp swings, many say that it is actually good for the health of your corals.
Also, I remember reading somewhere that the shimmer lines actually do have a huge spike in par. He actually tested this with a par meter and was registering spikes in par on shimmer lines. And also commented that sps responded with excellerated growth when a lot of shimmer was present in the tank. He monitered the tank with the flow directed so the surface was lightly agitated, and again with the flow directed so the surface was fiercly agitated. He did both for several months and noticed the sps responded with faster growth to the latter. Now maybe it had to do with greater gas exchange and different flow orientation, but with the results of the par test and the surface agitation test, I'm inclined to believe that shimmer lines do have benefits to coral health/growth.
I think you can really get the colors out of your corals more readily with t5s just cause you can introduce the color spectrum that certain corals respond to. Once you have found all the colors that pop all your different corals and use them in combination, your whole tank will really POP. I think metal halide gives a much more natural, sunlight appearance...more of a shallow reef look. whereas T5s look more deep water...
! I'm a huge equipment noob so the more broken down the explanation the better.
