Help Me Understand...Lighting ??

[izoid]

I currently have a 120 with a Coralife Aqualite Pro (2x150 MH and 2x96 PC) I have been told that this fixture is not enough to keep SPS except at the highest points within the tank. It has been suggested that I get an 8x54 watt T5 fixture and that light would be more than enough for SPS.

I am trying to understand how 492 watts of MH and PC are not enough light while 432 watts of T5 are more than enough. Please help me understand the dynamics at work here and if you agree with the idea that I need the T5 fixture for SPS.

 

[lilrobb]

The "intensity" of a light determines water penetration.
96W of PC are neglectable for corals and do more for the human eye.
MH are generally pretty good, but 150 are on the low side - I have however seen thriving tanks under 150s.
T5s are my personal favorite - I have the 8 bulb and if you wanna swing by I can show you the differences on a PAR meter.

 

[crew]

The thing with T5's is that each bulb has an individual reflector (in a good unit) which means much more actual light making it in to the water.

Personally, I am a T5 fan, like Robb. On top of great growth and color from all my corals, I also have much more personalization options as far as color goes. MH's are one solid bulb, but with T5 you get 8 different bulbs meaning you can mix in match.

 

[grouper therapy]

Lumen per watt for metal halide and Ho T5 are relatively the same with the Ho T5 having a slight edge around 90 and 100 respectively. Power compact only have around 65 per watt.

 

[lilrobb]

grouper therapy;675372 wrote: Lumen per watt for metal halide and Ho T5 are relatively the same with the Ho T5 having a slight edge around 90 and 100 respectively. Power compact only have around 65 per watt.

Much more scientific than my explanation, but just as correct! Haha

 

[mph84]

I had the exact same fixture on my 120 and grew large sps colonies. if you look at my totm page you'll see what you can do with one. I do have to say though, you have to have them pretty close to the water. which in turn puts a lot of heat in the water. I upgraded to 250's and love em!