Very basic questions about double-ended HQI

[wgscott]

Today I was in a LFS and looked up into a pendant that had 2 150 W double-ended metal halides. It was a lot brighter than expected. I am still hoping to regain full use of my right eye.

This was the first time I have been genuinely impressed with light output from metal halides, given the wattage. It seemed clear to me that two 150 W like this would be more than adequate on my 55 gallon, and likely would have cost less than my current 400+ W of PC, at least to purchase.

Here are my questions:

What is HQI and why is it better than standard metal halide systems?

Are all HQI lamps double-ended?

How much more light do you get out of say a 150 W double-ended lamp vs. a conventional 150 W single-socket halide of the same color temperature?

How efficient are they? What does 300 W of double-ended lamp actually consume? I understand the ballasts eat a lot of electricity, so 300 W is probably an optimistic lower bound. How does it compare to 300 W of ordinary halide? 300 W of compact fluorescents?

How much heat do these things produce relative to say a standard metal halide of the same wattage?

Do you have to buy them as pendants? Will they overheat if you stick a pendant in a canopy?

Would my electric bill be less for 300 W of double-ended halides vs. 440 W of compact fluorescents?

Sorry these questions are so basic but I have tried to ignore halide lamps because I thought that I couldn't afford to run them.

[Ninong]

Originally posted by wgscott:

Today I was in a LFS and looked up into a pendant that had 2 150 W double-ended metal halides. It was a lot brighter than expected. I am still hoping to regain full use of my right eye.

I'll swap right eyes with ya, no questions asked. [img]/ubb/biggrin.gif[/img]

This was the first time I have been genuinely impressed with light output from metal halides, given the wattage. It seemed clear to me that two 150 W like this would be more than adequate on my 55 gallon, and likely would have cost less than my current 400+ W of PC, at least to purchase.

A single 150w 10,000K HQI double-ended is more effective than a 175w mogul base metal halide lamp. Some LFS even go so far as to say it is almost as good as a 250w metal halide lamp. Yes, two 150w HQI double-ended lamps would be sufficient for a 55-gal tank for most people. You could have purchased a very nice ready-made fixture with two 150w 10,000K HQI double-ended lamps for only $400 about a month ago at Champion Lighting. They had reduced the price on some of the Aquastarlight Classic fixtures in 4-ft lengths.

What is HQI and why is it better than standard metal halide systems?

HQI = Mercury (Hg) Quartz Iodide
There seems to be a difference in performance between lamps connected at both ends and mogul based lamps connected at one end only. There may be differences in the metals, but I'm not sure of that.

Are all HQI lamps double-ended?

No. For example, AB-Aqualine makes double-ended metal halide lamps in 70w, 150w and 250w sizes. They also make mogul base HQI lamps in 250w, 400w and 1000w sizes. The strange thing is that the 250w HQI double-ended lamp not only produces more PPFD (PAR) than the 250w mogul base HQI lamp, it even produces more PPFD than the 400w mogul base HQI lamp. Sanjay has tested the Ushio/BLV 250w HQI double-ended lamp, the 400w Ushio/BLV mogul base HQI lamp, and the 400w AB-Aqualine mogul base HQI lamp.

How much more light do you get out of say a 150 W double-ended lamp vs. a conventional 150 W single-socket halide of the same color temperature?

You have to compare it against the 175w mogul base lamp. The 150w double-ended HQI lamp produces significantly more PAR than any 175w mogul base lamp, which varies depending on the brand of 175w lamp. I do not know how it compares against the 150w 6500K Iwasaki medium base lamp.

How efficient are they? What does 300 W of double-ended lamp actually consume?

The only report that I read was about two years ago and I remember the author bragged about them in every possible way. He also claimed that they would easily last 18 months. I have read that you should replace the 150w HQI lamps every 18 months and the 250w HQI lamps every 15 months. That came from the manufacturer and is based on 10 hours per day.

I understand the ballasts eat a lot of electricity, so 300 W is probably an optimistic lower bound. How does it compare to 300 W of ordinary halide? 300 W of compact fluorescents?

I really don't know for sure except that I would be inclined to favor the HQI double-ended.

How much heat do these things produce relative to say a standard metal halide of the same wattage?

Only a little bit less.

Do you have to buy them as pendants?

No, but you must use a UV shield with these lamps. It is not an option. You MUST use one.

Will they overheat if you stick a pendant in a canopy?

JG has them in his canopy. Golfish has them in his canopy. PerryinCA has one 250w HQI double-ended lamp in a DIY arrangement next to a 250w 6500K Iwasaki over his 90-gal tank. So far, he prefers the HQI over the Iwasaki.

Would my electric bill be less for 300 W of double-ended halides vs. 440 W of compact fluorescents?

Probably.

Sorry these questions are so basic but I have tried to ignore halide lamps because I thought that I couldn't afford to run them.

You should have asked me. [img]/ubb/biggrin.gif[/img]

Ninong [img]/ubb/smile.gif[/img]



------------------
Irrational Exuberance!

[MtnDewMan]

Excellent response to those questions Ninong, maybe good for the archives?

I too have my 250W HQI pendent under the canopy. To give you an idea of how it looks under a canopy, here is a picture:

[naser]

dew!!! do you have a chiller?

[MtnDewMan]

No Chiller ... I have 2 4" fans ... one at 78cfm the other at 96cfm ... am planning on changing out my 78cfm fan to 96cfm for the summer months. Also may use a lower heat generating return pump for the summer months as well. A chiller is definately my last resort for the summer.

[wgscott]

Do the fans blow over the water, or is there a piece of plastic or glass in between?

[golfish]

Here's a few pics showing how I have mine setup. You can't really see it but I also have a fan right behind the 400 watter in the middle....HTH

[MtnDewMan]

I don't have any glass over the water, so the fans both blow inward across the pendent over the water. I have about 1 1/2 gallons of evaporation a day with my current setup.

[naser]

golfish... who made your canopy?????

[golfish]

Naser,
I'm not sure who made it, a shop in Montery Park I think. I ordered it from Neptunes Reef in Torrance. I do NOT recommend them or the builder of my stand and canopy. The canopy isn't bad but I had to rebuild the stand. There was no way the stand would have supported the tank full of water they way they built it........

Mark

[naser]

im looking for a nice tall canopy for my 55 i want to house to mh and some pc's... im looking for about 20 inches tall i think? that should give me room to play.

[chromis]

do double ended need a HQI ballast? If they do that brings the price up alot. Would 1 150 double ended be enough for a 55 with 110 watts of PC?
thanks
Andrew

[golfish]

Naser, Look around the different LFS and you can also chech your local cabinet maker...

Andrew, Yes they need an HQI ballast. How long is the 55? Off hand I would say no, you need two bulbs....

[Ironreef]

55g 4' should have 2 but if you have 110w pc and want to ugrade it wouldn't hurt just to add one 150w in the center.You will like it you can always add another later

[chromis]

standard 48" long 55. A guy at a maryland fish store who was running the double ended lamps said I could put like sps and clams in the center of the tank and my softies on the sides. This seems like it would limit aquascaping to me. If I had to get two I would just get regular old iwasaki 175's. Double ended sounded real good the way Ninong put it. But it would be like $350. A little to much for me right now.