Difference between DE & HQI

[b_james]

Is there any difference?

[mr_alberta]

HQI is actually misinterpreted to mean DE. HQI is just a line of bulbs by Sylvania IIRC and comes in both SE and DE configurations.

[TheReefGeek]

Wow, didn't know that.

So for most reefers they mean the same thing, as in if they say DE, they mean HQI.

[mr_alberta]

I also should note that HQI stands for Halogen Quartz Iodide or something like that.

[b_james]

Originally Posted by mr_alberta

HQI is actually misinterpreted to mean DE. HQI is just a line of bulbs by Sylvania IIRC and comes in both SE and DE configurations.

So a DE bulb should work in a HQI fixture? And because they are the same they would both have similar output ratings? I always here people saying that HQI perform similar to a bulb with a higher wattage but with less power consumption. If DE are essentially the same thing then it opens up more options for me

[Delphinus]

DE lamps use different ballasts. The ballasts are often referred to as "HQI" but "HQI" is used to describe a lot of things. In 250W it means ANSI M80 ballast, but there's no such thing as 400W HQI, but the term is still used. A 400W HQI ballast is really a ballast for a 430W HPS lamp but can be used on a 400W MH lamp. I don't know what ballasts are used for 400W DE lamps.

Anyhow you can run a SE bulb on an M80 ballast. The technical details get quite into the nitty gritty, but basically the voltages and amperages and whatever else is used to drive these lamps are done so at levels closer to European specs, so these tend to be "more optimal" ballasts for a lot of our lights we use in this hobby, because those bulbs tend to come from Europe in the first place (well, originally they did, anyhow, or so I've come to understand). You have to of course understand it's not a fair apples to apples comparison because European electricity is not the same as North American electricity. 50Hz vs 60Hz, 110V vs 220V, etc. etc. etc.

Confused yet? I sure am. Let me try again:
- 250W DE isn't really brighter than say 400W. That's a bit of an urban myth. But the reflectors tend to be very good, so you get a very focused light out of a good DE fixture whereas you might not get that same focus out of a cheap SE reflector.
- DE lamps tend to have a lower profile fixture so they are better in some applications, for sure.
- DE lamps require a "HQI" ballast but the term "HQI" is potentially being misapplied. For a 250W DE lamp you want an ANSI M80 ballast, for a 150W DE lamp you want an ANSI M81 ballast. You can call these ballasts "HQI" and people will know what you mean.
- There's no rule saying you can't try to run a SE lamp on one of these ballasts. In some cases (or all cases (??), I don't know) you will get improved performance on a SE lamp using these ballasts because the ballast is "driving" the lamp (probably not the best term to use, but I'll use it anyhow) closer to its original specs than other ballasts.

[b_james]

Holy geez

So if I understand this properly I should be able to use a DE bulb in my Aqualight Pro HQI fixture with no noticable change in output performance?

[Delphinus]

Um .. Ok now I'm confused. Doesn't that fixture already use DE (double-ended) lamps? Or are you asking if you can use a SE (single-ended) lamp in there?

[OCDP]

Yup, Aqualight Pro's run off of DE bulbs.

[TheReefGeek]

The only bulb type you can run in that fixture is a 150w DE. You can pick your brand of DE bulb and the color temperature.