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What is HQI?


mje113

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I've been shopping for 150watt MH's and keep seeing HQI's and non-HQI's... what's the difference? (I'm assuming that the HQ stands for High Quality, but would like to hear someone else confirm that for me)

 

Thanks,

Mike

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you still didn't answer that IT IS...

 

i don't know and im eager to find out because im looking for the same thing he is

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all i know is its a double ended (DE) bulb that gives intensity similar to that of a 250W SE MH.

it also produces more uv and needs to be behind a "uv shield" more than that of SE bulbs

im sure someone else will chime in with the specifics

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neanderthalman

HQI is very good, but you have to mount them behind glass - no biggie.

 

HQI means Mercury Quartz Iodide, as Paladin already mentioned. The H comes from the chemical symbol for mercury, Hg.

 

If you notice, the Mercury is a metal, and the Iodide (Iodine) is a Halide (Halogen). Hence... Metal Halide.

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neanderthalman

That's open to debate. All glass will absorb some UV light. UV glass will absorb more. If you want UV glass, keep in mind that in most applications, you need the glass to also be tempered because of the heat.

 

UV glass won't do anything for you if the heat shatters the glass into your tank. I use regular tempered glass on my new MH fixture, but the tank is still cycling at the moment. There are many people using a MH modded into a regent halogen fixture, just as I have, without problems, and they have tempered glass - no UV. Halogen lights don't produce much/any UV, so they won't bother putting UV glass on the fixture.

 

If you insist that UV glass is necessary, despite the anecdotal evidence to the contrary, make sure that you use tempered UV glass.

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Thanks for the info...

 

ok, so then HQI is considered "better" than a regular MH (still not 100% sure on why), but if I wanted to avoid the hassle of mounting it behind glass, can I assume that I won't need to with a regular MH bulb? And would a reguler MH bulb be good enough?

 

Thanks!

m

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Undertheradar

HQI is a branding, or certification, much like Lucas liscences theaters with THX. The THX is a certification that the theater abides by certain minimum standards for acustics and video. HQI is very much like that. It is like an 'elevated standard' for halide lighting. The name itself it owned by OSRAM, of the Sylvania Lighting Corp.

 

What it means to you is that a HQI ballast will run the bulb at a higher output and power than any other ballast...higher than american probe start, euro-spec pulse-start, or electronic. These ballasts are thought to be the highest output ballasts for any given bulb. A typical electronic ballast might use about 275 watts to run a 250watt bulb, but a HQI can use up to 350!

 

There is a trade-off however. While initial results with HQI are the best around, the long-term tests show that HQI ballasts burn out the bulbs faster...by the time a HQI bulb is changed, about 60% of its output is lost. For this reason, many lighting engineers push electronic ballasts which are shown to run halides within their original operating specs for much longer.

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Undertheradar

That or an electronic ballast (icecap, blueline, etc). I would run a 10,000K on a HQI...the effects arent as big with 10,000Ks, but if you every intend on running bluer bulbs (14,000K or 20,000K), you might go with the electronic over the HQI.

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A HQI bulb burns a little hotter and thus brighter, partly because they have a longer ARC inside the tube. An arc-tube is the core on the inside of the MH bulb. It looks like a smaller bulb inside the bulb with the two currents connecting at both ends. The concept is the bigger the arc, the more gas that gets agitated and therefore more light is produced.

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Semi, I think you may still be a little confused. HQI=DE. Their are two types of 150 watt bulbs, but 95% of them are double ended (the other type is a medium base, more common in japan). HQI is just a brand name. UTR is correct with the ballasts. M102 150 watt ballasts will also fire 150 watt de bulbs, just without AS MUCH intensity (its still pretty intense). Electronic ballasts have the same effect basically, they don't push the bulb as hard (plus they are more effiecent).

 

Sam

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Undertheradar

Samc, uh, hate to crash the party on ya, but HQI does not mean DE. HQI refers to a ballast spec (and sometimes the bulbs that are designed for these ballasts). HQI often gets paired with DE, but a DE bulb can also be run at the pulse-start spec, and e-ballast.

 

Double ended bulbs are just that, and in fact were designed for the euro-spec pulse-start ballasts in mind. All 400 watt bulbs (until the recent DE ones that some companies have started making) are single ended, HQI or not.

 

I just want to make sure that everyone knows that just because you see a DE bulb when you are looking to buy, check the ballast as well...it might be a POS.

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I know EXACTLY what I am talking about, it might not have come across clearly! Sylvania Lighting Corp. designed the HQI ballast spec (essentially the M81 ballasts for 150 watt de bulbs) AND HQI bulb spec! Their are HQI bulbs, which are double ended bulbs made by Sylvania, and their are HQI ballasts (which you clearly defined above). However, as far as I know, they are interchangable (except for a few specific bulbs), so the HQI ballast will fire standard de bulbs and most electronic ballasts will also fire HQI bulbs. That is why it is confusing!

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Undertheradar

Ok, I just want to make sure nobody goes away thinking double ended means HQI. A double ended bulb may not be HQI, and can be operated with a ballast other than HQI, and a HQI ballast could be used to power a non-double-ended bulb.

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