i have decided to upgrade my lights. i have a 180 gal w/ 3x150 mh's and 4x96 watt pc's. i want to do mostly sps (80%) so i am trying to decide between 3x400 watt 20k mh's and 7 x80 watt t5's and a 160 watt vho bulb. thoughts suggestion?

Well first how deep is it? I guess a standard 180 is 24" deep. And then do you have a DSB for another 4" off that?

I am not set up yet but leaning towards T-5s on my 90gallon (also 24" deep). I'm planning on 6 retrofit T-5 bulbs initially but there would be room to go up to 8. Using less energy and less heat sells me on them. And I think T-5 can do the job.
Here's a couple nice T-5 SPS tank links that Reefbaby gave me...

Incredibly Simple - Reef Hobbyist Online Magazine (http://www.reefland.com/rho/0106/feature8.php)
Hausriff.ch-Seite für Meerwasseraquaristik (http://www.hausriff.ch/4477/index.html)

yea i have a local guy who runs his 180 with the same configuration so thats why i was looking at them. i like those features but i am a bit skeptical as it would make since for everyone to use t5's over mh's. doesnt mean it doesnt work though

I think MH (especially 400W) will get better/deeper penetration. Of course you might be able to get away with 250W halides also. 3x400W seems like a lot. I think T5s aren't around as much just because they are newer. They seem to be in use much more in europe. Like the new LEDs, not many out there now, but someday nearly everyone might use them.

for all the reasons you mentioned it would be a good idea to use t5's as i have seen more folks on reef central and the like using them. i dont know much about par and what the readings should be. also the reson i was looking at 400 watt lights is because the 20 k's have less par then 250 watt 10k's. or maybe a third option could be to get 250 watt 10k's with t5 supplementation and run the halides for like four or five hours a day

anyone know if 1 250 and 2 39 watt t5 hos would be good enough..like if the 250 leaves dark spots, are the t5s strong enough to light those areas and keep a coral there?

I don't know much about the PAR either. But if you want the 20k look then maybe you do need the 400W. Maybe because they are bluer that might be what also limits the PAR output in the 20k bulbs.

I am far from knowledgable on the subject, but have read articles that talk about the actinic spectrum being better for enhancing pigmentation, but the daylight spectrum being better for growth. (I think that is right, though I may have swapped them.) Maybe research that some and consider what your goals are there also.

you are right about that. the blue spectrum in mh bulbs is lower in par however the opposite is true of t5's where the bluer bulbs have better par. thats another reason

I am far from a lighting expert. However the MH are going to cost almost twice as much to operate. One reason that some people prefer MH is the glimmer lines.

Here are some various par readings that I got oof of reefcentral. I used them in deciding what kind of bulbs I was going to get.

The GE 3000K had a little more PAR than the 6500K, I probably wouldn't try it with just 4 lamps. Their is a long thread on reefcentral regarding T-5's. Personally I love em..

ATI
Sun Pro 357
Aquablue 336
Blue Plus 311
Actinic 137

D&D/Giesemann
Midday 325
Aquablue 324
Actinic Plus 264
Pure Actinic 157

UVL
Aqua sun 345
Actinic White 293
Super Actinic 210

AquaZ
Sun Pro 285
Ocean Pro 323
Blue Pro 266

Helios
Daylight 309
Super Blue 225
Current Sun Paq
Daylight 10K 272
Blue 252

GE Daylight 340

Metal Halide is superior. Period.

T5s is not a new technology. T5s have been around longer than some some of us. T5 bulbs have been used for aquariums before metal halide. T5s benefited from recent improvements in electronic ballast and reflector technology that fueled its latest comeback as that is no more than a fad.

If you can manage it, halide is the way to go. Anything than that, you'll just justifying at every occasion why you chose less.

Just my 2 cents.

Metal Halide is superior. Period.


Just my 2 cents.

This man is correct.:cool: At least if you are keeping animals/specimens that photosynthicize (sp?), there is no comparison. I swithced from T5 to a MH/PC system of only slightly higher wattage and the degree the tank has taken off is astounding. I wish I'd have taken pictures.