Watts vs Watts

[MeTaLMaN1375]

Ok Im having a hard time understanding something hopefully someone who knows something about it can clarify this for me. I understand that lets just say for example you have a reef and you dont want to be limited as to what you can keep theres a formula that is wattage per gallon dont know the actual numbers off the top of my head and I understand that it may vary a bit depending on the depth of your tank but for the most part more wattage the better without over doing it dont want to cook your coral. But what Im trying to get at is that I have a PC lighting 2 white bulbs 2 blue bulbs 96w each bulb which equals 384w. But Im told that t5ho that are 4 bulbs at 54w each which equals 216w is better than my power compacts why and how is that?

 

[bongarone]

Power compacts output less usable light than highly efficient T5s of comparable wattage. Watts is a measurement of electrical power consumed and is more or less irrelevant.

 

[James77]

The linear shape of the t5s enables highly efficient reflectors and active cooling. PCs are bent so that in itself blocks light, plus that width blocks any reflection from behind.

 

[tomservo]

PC and T5 are based on very similar technology. The differences, as above, T5 reflectors make a *huge* difference - 300% brighter with a good T5 reflector vs no reflector. T5 NO (normal output) are hugely efficient, but lack the intensity we need. T5 HO (high output) are a very good balance between efficiency and intensity, pretty much perfect in a tube light. Power compacts are like a VHO or SHO version of T5, so the efficiency is not so good, and the heat produced as a result is substantial. Hence, they tend to burn out their own phosphors early, meaning more frequent replacements. Then add to that, you can't get a really good reflector.