Difference between DE & HQI

[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.

[SeaHorse_Fanatic]

HQI - Mercury (Hg) Quartz Iodide

HQI I believe come in both SE & DE.

Somebody asked me tonight so I googled it.

[StirCrazy]

Originally Posted by SeaHorse_Fanatic

HQI - Mercury (Hg) Quartz Iodide

HQI I believe come in both SE & DE.

Somebody asked me tonight so I googled it.

Bingo

Ok Like Delphinus and other have said, the term HQI is abused and not used properly at all in our industry. The HQI ballast is built to replicate German reactor type ballast outputs and comes in several different wattages, 50W , 70W, 150W, and 250W. (If they are making a 400W now I have never seen it) but I believe they use the Son Agro ballast for the 400 watt HQI (DE) but I am not sure.

now a 250W HQI ballast will drive any 250W bulb on the market but a DE bulb has to be driven by a HQI ballast. make sense?

so there is a difference in the bulbs a DE needs a DE holder, they are smaller profile and will put out close to the same light as most 400W set ups, but a 250 watt (quality bulb) SE run on a HQI ballast will put out more light than than most 400W systems and with reflectors thrown in the results can be amazing.

the DE bulb is great for tight spots, smaller tanks (less of a foot print to run say 2" x 2" at a max) where the SE will light a 3ft x 3ft spot with about the same amount of light intensity. Also there are a lot more choices in lights on the SE side but DE is getting better.

Steve