Need advice on a used light set-up

[Jamie]

I'm sure most everyone has a better understanding of this stuff than me, but I've done a bit of research...forum scouring and such, and have found out a few things...just thought I'd put it out here to share in case I was off the mark.

It seems that there are a few things to look for in a light source...lumins, lux, photosyntheticaly active radiation (PAR, 400-700nm) etc. From what I've read, it appears that PAR is the best measure of how effective your set-up is because it's measuring useable light that your corals can take advantage of. From what I've read, the drawbacks to VHO compared to T-5's is that the VHO's have very low PAR and poor penetration compared to T-5's. WPG doesnt tell you anything about how well a light set will keep corals...it all depends on the PAR.

One guy from another forum has access to light measuring equipment and posted some PAR results. The lights fixtures in the test were suspended 15" above the water and the light was measured approximately 15" underwater...

Solaris LED(2ft model) was 70
216 watt T-5's on spec balllast was 150
250 Watt DE MH was 175
260 watt PC was 50

This would confirm that MH's are the best, but surprisingly, the T5's did remarkably well in comparison. When you argue efficiency, heat, and bulb life expectancy...it almost seems that T5's are the way to go. Granted, you can definately cram more wattage, and hence a greater overall PAR, with MH's. Though there isn't any data on VHO's, I've read that they're only a little better than PC.

I'm sure that there a different variations of each set-up that could be better or worse...I'm still new when it comes to recognizing good and bad brands. I can only assume that these fixtures are a good representation of what each typre of lighting has to offer.

After reading up, I think I've got a better handle on lighting considerations. Does anyone have any other input? Am I on the right track regarding my understanding of light set-ups?