MH Questions

[Tarasco]

All right, I'm planning on upgrading my lighting soon, and I just have a couple questions. What is the main difference between Double Ended and Single Ended? I know that DE's are supposed to be better, but why? Also, what is HQI, and is it only available in pendants, or can I get it in a retrofit kit?

[mps9506]

The main reason DE's have such better results in test are becuase the smaller size allows for a better reflector design.
When most reefers taslk about HQI they are referring to the type of ballast you are using. MH ballasts come in four flavors; probe start, pulse start, HQI, electronic. HQI generally puts out the most omph, but also makes the power company the happiest.
If using a DE bulb I would highly suggest getting the electronic ballast.
I don't think you are going to find a retrofit kit for the DE's anytime soon, although you can purchase just the sockets for them. Therefore if you have an appropriate housing for them you can purchase just the socket and retrofit it. However I highly recomend using the pendants, take a look at Sanjay's test, and the pendants really improve the bulbs output over "retrofitted" DE bulbs that are put in quartz halogen housings.
Keep in mind that the DE bulbs have no outer glass housing to block out UV, there they must be used behind some type of glass or you risk seriously burning your corals.
Hope that helps a little bit.
Mike

[Tarasco]

thanks, appreciate the answers. what do you think of these? price looks good...

http://diyreef.com/shop/product_info...roducts_id=176

[Boomer]

Also, what is HQI

HQI = Halogen Quartz Iodide, aka, Tungsten Halogen, Quartz Halogen, common out door garage and car headlight.
These are similar to conventional non-halogen incandescent light in that it employs a tungsten filament in a gas-filled, light-transmitting envelope and emits the same type of light.


or

HQI = Mercury Quartz Iodide ( where H is the first letter for Mercury in its chemical symbol, which is Hg. The arc tube is filled with gases (normally argon) along with mercury and other metals (e.g., sodium, lithium, thallium, indium, scandium, Thorium and other "soft silver metals", which give it its K value.) in iodine/halogen salt form, thus the name metal halide (halide refers to mercury content). These are one of the HID lamps, High Intensity Discharge, as are MH, HPS (High Pressure Sodium) and MV (Mercury Vapor). LID's, Low Intensity Discharge, are fluorescent lamps. Both types are a form of Plasma, where incandescent lamps just more or less heat up a filament. In LID lamps the Argon gas produces no light, whereas in HID the gas does produce light. The real purpose behind the gas is to increase internal bulb pressure. In other words, the gas produces or allows more lumens / watt of light. For as gas pressure increases light efficiency increases. and thus less watts of power are need to produce the same amount of light. So, in short, removing the gas from the bulb would give the bulb less light output.

One needs to be careful with terms, as these two lamps are not the same buy ay means. An HQI incandescent puts out no more light than about 20 lumens / watt, whereas a HQI, MH can approach 4 times or more than amount of light.