<a href=showthread.php?s=&postid=11239250#post11239250 target=_blank>Originally posted</a> by Shouse94
Also why do you choose to replace your T5 bulbs every 6 months?I only ask this b/c I've heard from other reliable sources that T5's hold their light output curve waaaay longer than Metal Halides and don't really begin to lose efficiency till near the end of bulb life (which is way longer than 6 months). I'm not questioning your strategy, only trying to understand from your point of view/experience. Thanks for any insight you can provide. 
<a href=showthread.php?s=&postid=11238706#post11238706 target=_blank>Originally posted</a> by njdevilsfan
im sorry if im repeating a question
why do you replace the t5 bulbs after 6 months?
<a href=showthread.php?s=&postid=11239250#post11239250 target=_blank>Originally posted</a> by Shouse94
Well you are but I still haven't got a response yet.
Sorry for delay in answer to your comments.
Shouse9 and njdevilsfan: Soon or late I will answer to all questions with all pleasure of the world.
Changing t5 every month is really expensive. The idea that I have about lighting used in reef keeping is that, even with t5 bulbs, we can see clearly drastic changes in color temperature after few weeks after use. The lamps tends to show a significant reduction of its intensity in the first six months of life but it is difficult to assure the reduction of intensity when used for some time after that "deadline". Is accepted by all that as the lamp ages the intensity will reduce. One way to counteract this situation, not a practical idea!, would be put the fixture furthest from the surface of the water when the lamps are new and go lowering the fixture as time goes in order to maintain the intensity at the water surface, but the problem of the spectrum of light bulbs that will change with time also, it would not be resolved.
The intensity of the lamps are reduced sacrificing the violet and blue radiations "left zone of the spectrum" keeping more or less stable the right yellow and red zone of the spectrum. We note that the loss of intensity is higher for blue lamps, with high kelvins, which tend to be more white when ages but the same is not true with lamps with wider spectrum, around 10,000 ° K.
It is true that there have been large technological developments in the manufacture of t5 and electronic ballasts have brought significant improvements not only at the level of intensity of the lamps but also the stability of the spectrums, bringing in much life to the bulbs, but as a matter of caution i change my lamps with high kelvins every 6 months and the bulbs with low colour temperature can go up to 8 (10 months at most). To prevent light shocked i avoid sudden increases in brightness when i change bulbs I change few bulbs at a time.
Cheers,
Do you have problems with it floating up when empty? I quess you must weight it down untill you place enough frags on it .
