I'm running the two side by side right now over my 90. Couple observations I have made.

1) The visual intensity is pretty even, however the spread of the Iwasaki is better than the mini-pendant due to the use of spiderlight reeflectors.

2)The difference in color is noticable, but not extreme. The Iwasaki still looks white next to the HQI, but is more of a warm white. Both are pleasant.

I am running both of them on identical Icecap ballasts. Tomorrow I am gonna install a Icecap ballast tuned for the DEB(double ended bulb) and compare color/intensity. I doubt there is going to be a huge difference, but we'll see.

As for coral coloration, I have a couple frags from the same parent colonies, and will be running lights as they are to compare colorations a month or two down the road. I don't have any hypothesis at all right now, but I am hoping for more pronounced bluing of the frags under the HQI. We'll see.

So far I think the HQI is a good lamp. Nice color, intense, doesn't really need supplemental actinics IMO. However, I don't consider them a huge "upgrade" to the Iwasaki. In fact I don't know if it really warrants the money to go from 65k to HQI, but thats really personal preference. I like them both, but had I to do it over again, I'd probably save the money and keep the Iwasaki.

We'll see if my opinion changes in the coming months. If I see better coloration, I'll likely back the HQI more strongly.

Now most of that is said concerning the 'upgrade'. I think that if you are buying the stuff for the first time, why not go with HQI? If you really like 10k there's nothing that will beat it. Its a bit costly, but is the way to go if you like the cool white look. They both look good to me.

HTH, and ask if you have any further questions.

Perry

------------------
Some call it evolution,
And others call it God.
Each In His Own Tongue (1908)
William Herbert Carruth 1859-1924

If you don't use actinics you may want the double end hqi. iwaski seem to visually wash the colors. But IME 2-250 w Iwaski with 2-110vho looks the same as 2_250 10k. But I'm using 2_250w Iwaski and 3_110vho to save energy. I was thinking of using a 400w 10-20k for blue.+ 2_250w. But IME Iwaski colors the pigment in my sps more than 10k. But other factors apply to that. the tank I got my frags from didn't use a calcium reactor. So my water quality may just be better. IMO you have 10k now? If you sps looks good you may want to invest in or retune you ballast to hqi double ended. You don't use actinic? But if you are getting another ballast you may think of 400w 10k if power isn't a prob for you? I"m on a buget thats why i have 250w private violen/piano take away from my hobby allowance. But I did manage to get a full head of sps today [img]/ubb/smile.gif[/img] Hope it colors nicelly.

Thanks for the replies. And yes, I do have an Iwasaki currently ... so it would be considered an upgrade. I have tried the 250W 10k single ended for a few days but too much feedback told me it wasn't enough intensity compared to the Iwasaki. But I like the coloration of my tank so much better with the 10k. So if I were to upgrade, of course I would recoup some losses by selling the old MH system.

Definately still in the thinking stages, thanks again.

I run 2x250watt 10K HQI's, IMO, the light is close to the same as far as par goes but the color is not even close.....

Anyone have any experience to compare the two here? I really prefer the look of the 10k bulb over the 6.5k bulb. I have heard that the 10k HQI bulb has the same intensity if not more than the 250w 6.5k ...

Can anyone comment? Anyone using the mini-pendant system that can be mounted within the canopy?

Any info would be appreciated.