MH vs. T5... Why so much push for MH...

[OrionN]

Several things
1. LED is a lot more efficient that MH or florescent light, therefore, for the same amount of light out put LED use a lot less energy.
2. On the other hand T5 is just florescent light, the same technology we had for years. T5 technology is nothing new other than the smaller bulb size. The advantage of small size (T5 vs VHO or PC) bulb is better (smaller) reflectors. In order for the reflector to be any good it needs to be much bigger than the bulb or else the bulb itself will block a lot of the light.
2. When to replace the light, we all know from experience. I replace my MH bulbs at anywhere from 12-18 months. Some bulbs degraded faster than other. The Chinese knocks off bulbs are great. I used them for many years now and my corals, clams and anemones are dong just fine. I see no different in result from these bulbs from name brand bulbs. In fact these bulbs are much better than the stock bulbs that originally came with the fixture. Not one has exploded on me or any disaster befalls my tank after all these time. That is disaster due to bulb malfunction. I had plenty of disasters due to other causes.