What exactly is "HQI"

[The Unit]

What exactly is "HQI"???????????

[Casino]

Where have you seen this?

[JazzMan]

:rollface:

[The Unit]

Riiight.....so what is it.....just another MH as far as i can dig up...right

[BonsaiNut]

HQI = Mercury Quartz Iodide (the "H" stands for "Hg" the elemental symbol for mercury)

Now that information and a quarter will buy you a nice gumball :)

And for some additional acronyms; HQI lamps are a special type of HID lamp (or high-intensity discharge). There are three types of HID lamps: Mercury Vapor, High Pressure Sodium (sometimes known as HPS), and Metal Halide. HQI lamps are a special type of metal halide lamp.

[The Unit]

thankyou for the reply.....now i can get a 70w HQI for my 15gal...but it dosent come with a UV sheild.....where can i buy one?....now i understand it is for the radiation...correct?.....does this sheild have to completly surround the bulb?,,,,,,,,,,thanks for the reply

[SeaStar]

A simple piece of glass will suffice. The shield only has to be between the bulb and the water surface. However the uv it emits can possibly be dangerous to you with prolonged exposure. Depending upon your setup you will want to protect yourself from this via a canopy or other method.

[Boomer]

One needs to be careful with the term HQI, as it has to different means in light bulbs

HQI = Halogen Quartz Iodide

HQI = Mercury ( Hg, - the g) Quartz Iodide

The first one usually is associated with special high output incandescent lamps, some times called Tungsten Halogen. Many of these lamps are double ended just like the Euro HQI. You have seen them before in hardware stores. They are about the size of a cigarette and are often used for outdoor lighting


Halogens (http://www.chemicalelements.com/groups/halogens.html)


Here is how the bulb works.
HQI Tungsten Halogen (http://americanhistory.si.edu/lighting/th.htm)


Here is what the double ended bulb looks like, bottom of page
Halogen doulbe bulb (http://www.adventurelighting.com/guide_shape.htm)


The Euro HQI, is a double ended MH. Both types of HQI look somewhat similar but work completely different. Here is an intro
Aquarium Lights (http://www.seabay.org/articles/let_there_be_light_3.htm)

As you can see from the diagram the double ended Euro HQI do not have the large outer envelope that the std tubular or elliptical MH have. They operate basically the same. Mercury is found in all HID lamps. The Quartz, is that the tube is mad of quartz, usually Borosilicate.The Iodide comes from on of the Iodides used to produce light, along with the Mercury and Argon gas. The Iodides are usually of rare earth soft silver metals;
Scandium Iodide, Thorium Iodide etc. The combination of these Iodides gives the lamp characteristics you want

Iodides (http://www.chinarem.com/english/products/sh.htm)


Metal Halide Operaiton (http://americanhistory.si.edu/lighting/mh.htm)

[BonsaiNut]

I think you are refering to Quartz-Iodine (not Iodide) Halogens. I have never heard of these bulbs being refered to as anything other than "Halogen" or "Quartz Halogen". In fact, with an Internet search of "HQI" I couldn't find any mention of them. Maybe if you were in the Army, you might have seen them listed as "Halogen, Quartz-Iodine" (as an ex-Army guy myself).

However (as you say) because they are incandescent, it is easy enough to see a difference, since there is a wire running through the middle of the bulb :) They are also dirt cheap - I have picked up Quartz Halogen fixtures (bulb and everything) for under $30 at the local hardware store.

It is certainly a good warning. If someone out there is calling their Quartz Halogen bulbs HQI, then we should keep our eyes open.

[Boomer]

No, they go by many names, e.g.,Tungsten Halogen, Quartz Halogen, Quartz Iodide, Iodine Quartz and yes I mean HQI incandescent? HQI, as incandescent lamps, have been called that for decades. Some times the I is as Iodine and other times it is given as Iodide. And many are trying to get the name changed to just Tungsten Halogen .The older name HQI is nowhere near as common as is was long ago, almost rare. The proper name should be Tungsten Halogen, as many Halogen lamps don't even use Iodine but Bromine, so we need a broader term. It can be a confusing issue, as MH HQI also stand for; Halogen Quartz Iodide, the H is not always from the H of Hg for Mercury but Halogen

[Gary Majchrzak]

Enlightening thread. A good candidate for a sticky.

[BonsaiNut]

(nothing to see here - move along)