asked similiar in this thread

Here was a reply fr hillbillyreefer who tried them:

They are a PITA on a tank. I've got 4 on my 33 gal. You'll need a 10 amp powersupply for each bulb. You'll need to figure out some sort of reflector. The ballasts get really hot and burn out quickly. I think they would be better in a car as the airflow would keep them cool. Not sure how long the lamps themselves last as the ballasts all fried before the bulbs. The light is decent and the bulbs are available in various K ratings. I never did take pics of them when they were running, it's too late now.

Save your money and buy a MH, way less hassle and better life span, in my experience.

Ok I feel these are getting a bad rap so lets go over the pro's and con's;ok people claim too much heat in ballast my guess is their calculations were wrong and the unit isnt being powered right(capactors and resistors) if not put a cpu fan on it,next they claim wrong spectrum...wrong they are allmost identical in every way,next they say they cost too much well...for a nano only 1 bulb is required...motorcycle units cost 89$and bulbs start at 9$ or you could split a car package worth 120$ with a fellow nano reefer the only other equip required is power source which go for 30$+ So then they say what about a reflector or hooking up supply....well if you cant figure that one out you shouldnt be doing diy lighting in the first place. From the research I've done I've found;they are cheaper to buy,run and replace bulbs ,the bulb produces less heat and is smaller and has equal par ratings.

In short if you have a nano 14g- and understand electronics I think it's a great technology that will only get better as more people use it,but I agree if you have a tank over 14g mh is the far better solution........but hey thats just one mans opinion

Not sure where you got that from. The key to any lighting is the bulb. Have you noticed that bulbs for the hobby are more expensive than similar bulbs used for other applications? Even the cheap ebay bulbs aren't much good. I doubt those bulbs will provide the required spectrum over time, at least not in an efficient way.

So you can get a 30W unit for $90 which only included the bulb and ballast and you need to run some inefficient power supply, what about a reflector? Oh right they don't make one. Also you can get a 70W MH bulb and ballast for under a $100 if you know where to look, that way you get more than twice the output and a proven spectrum. Did you know my SPS corals get great polyp extension when the lights are off?

I just don't see any reason in pursuing this, sure if you want a 5.5g but not much of a market there and anything bigger would benefit more from a 70W light.

You're going to have to hook up a PAR meter and measure these lights before you can make any claims.

Are you even reading what I'm typing? I mean really......the info i got was from much research online on one site they showed the par values which is why I mentioned the par value in my previous statement. Go online and look your self at the values;par is higher than mh 70w,10000k+ and wavelength is 430-470nm at 10000k now go check your mh specs,the only place it lacks is in the lumen department which aparently does'nt mean much to corals. There you have it...data....facts..... please show me something to prove otherwise because all I've heard so far is conjecture or one persons failed experience due to faulty wiring PLEASE someone direct me to data that says this cant work,otherwise open your minds!!lol

Link?

Here under ''what is xenon" youll find an article explaining how the xenon uses metal salts (mh) also how it achieves its kelvin rating through burn temp like an mh the xenon with the coatings are 12000k and higher ,the 10000k is entirelly burn temp.

I'll find you those stats may take a while though,sad how you think im lying to you....oh well http://www.delonixradar.com.au/products/hid/xenon.html

You get 404 error on the link....

Heres everything and anything you wanted to know about xenon,here youll find a graph comparing xenon to other lights including the sacred "cree" l.e.d
they explain how xenon is a micro mh that uses different gases for firing.
Check the graph and the paragraph next to it good food for thoughtwww.xevision.com/hid_products.html

Did I mention that last link sells parabolic reflectors for them lol

Just a note, Cree claims efficiencies of around 100 lumens per watt also, depending on chip temperature. http://www.cree.com/products/xlamp7090_xre.asp This is only one of Cree's LED chip products, and there are many other great white LEDs by companies such as Osram (Sylvania) and Lumileds (Phillips).

I'd be curious to see the PAR value of Cree's cool white LED products. I like LEDs for the fact that they are solid state ie: less prone to breakage, and they are rated to last 50 000 hours, though the actual useful life will be less for our purposes. A big detractor from xenon bulbs is the rated 3000 hour life, which is less than both MH and fluorescent... wow, hope the bulbs are cheap!

I'm glad that forums like this exist so that open discussion can make us think of new ideas. If xenon can produce higher PAR values, perhaps we will see the advent of 150w xenon metal halides in the future... though I doubt that the aquarium / horticulture segment of the total metal halide lighting market around the world would be enough for manufacturers to start producing larger xenon bulbs. If indeed the lumen output of these bulbs is lower than our traditional metal halides, I can't see these lights making it as a replacement as they are not fit for the traditional use of HID lighting (task and area lighting) even if the light is superior in terms of plant growth.

I still maintain that this (xenon) is probably the BEST way to light a pico to small nano (less than 10g), at least if you want SPS or other intense light requiring organisms and don't mind changing a bulb more often than usual. I suppose you could use PC, but then you don't get those glitter lines that I so love with MH lit tanks.