SE or DE?

[pickle311]

I'm ready to buy my lights and can't decide what to get. Here's my options. I'll be lighting a 120 and will be using 2 250W MHs. The will be run off of Coralvue E-ballast. All I need now are the bulbs and reflectors. I was either going to get Coralvue 14K SEs with Lumenarc III reflectors, or Coralvue 14K DEs and pendants. I'm thinking that the SEs will spread better and give an more even light across the tank and the DEs will be more focused. I know that DEs are supposed to have better Par ratings, but I'm not all that concerned about that. I know that either way I will have plenty of light for the corals. I'm more concerned with appearance that the lights will give the tank. Money is not and issue either because the cost is very close between the 2. What do you guys think? I've never used DEs before, or the Lumenarc reflectors.

[scuba_steveo]

I will go DE next time. Just cooler!

[scuba_steveo]

What kind of ballast do you have? Is it a magnetic HQI? If so, get DE bulbs. SE bulbs will not last as long on it.

[Brett Wilson]

I would choose DEs mainly because of the heat factor but also because you arent going to have to worry too much about light spread on a 4' tank with dual lights IMO. I could be wrong though, I haven't ran that setup myself...

Though in the somewhat distant future I can see myself asking the exact same question regarding a tank about that same size. :D

[pickle311]

Scuba Steve, I have the Coralvue e-ballast. I was also leaning towards DEs because of the heat issue. Since they are enclosed I don't think they put out quite as much heat. Heat is deffinately a factor here in the summer months. If I knew for sure that the DEs would spread even over the entire tank, I would have already orderd them.

[scuba_steveo]

No electronic ballast can drive a DE bulb to its full potential. It takes a HQI ballast to do that. The DE will probably be cooler can give enough spread, go with it.

[Tim Marvin]

DE, they have more par, cooler, and the pendants from coralvue spread VERY well. It is a much cleaner nicer set-up.

[Tim Marvin]

Actually the coralvue electronic ballast fires my DE much better than the PFO/HQI pulse start I had. Super crisp white.

[pickle311]

thanks for the replies, I think I may go with the DEs after all.

[GaryP]

I'm somewhat confused here. How are DE's cooler. They produce just as much heat as an SE. I can only assume you are referring to how the heat is vented out of the hood. Are you talking about the integral fans in the pendent? That heat is vented into the hood and will still need to be pulled out of the heat by another fan unless the air is somehow ducted out. Not being critical here, just uneducated on the operation of DEs. I have only used SEs.

[pickle311]

I'm trying to figure that out too. I seems that since it is enclosed, it will hold in more of the heat rather than being in the open like SEs. I'm sure I will still need fans in the canopy and will be using them. But just from looking at the construction, it appears that they will put out less heat, but I could be wrong.

[matt]

It's entirely possible that DE 250W bulbs produce less heat than mogule base bulbs of the same wattage. Why would that not be possible? One thing for sure is that there's less radiant surface, (they're smaller bulbs) so for them to produce the same heat, they'd have to run at a higher temp than mogule bulbs. I don't know if this is the case, but somebody must have done some sort of a study on this. I think Gary does have a point, though, most people use DE in a mini pendent over an open tank, which allows for much better heat dissipation as opposed to a canopy for mogule bulbs. Next tank I set up (whenever that may be....)I'm using mini pendents over an open top.

[aquadoc]

I use DE 250 HQI 14K, and 10K
The reason why they run cooler is because they are in a pendant. Every pendant has vents on the top, or sides(usualy the top). When the light is turned on it heats up, and which way does heat travel..... UP!
That is one reason why they run cooler too.
Another benifit using DE in a pendant is that it has glass protecting it from getting splashed, wich could cause the bulb to break.
I also think that they are alot brighter than the SE 250. They are usualy compared to 400 SE instead of the 250. This is because the amount of parr they put out.

I am realy happy with the DE 250 HQI. If I were you I would get the DE. In the long run you won't regreat it.

[GaryP]

I use DE 250 HQI 14K, and 10K
The reason why they run cooler is because they are in a pendant. Every pendant has vents on the top, or sides(usualy the top). When the light is turned on it heats up, and which way does heat travel..... UP!
That is one reason why they run cooler too.

Isn't that the same thing as a hood with SE that has vents in the top? The hot air still vents upwards. Most pendents I have seen have a fan that blows the air out the side. Isn't that the same as a hood with cooling fans on the side. I'm still confused as to the line of logic here. The bulbs don't actually run any cooler, its just a matter of how the heat from them is vented away from the bulbs and ultimately from the water. If, in fact, they do give out more light than an SE, wouldn't it make sense that they run hotter than an SE. Light isn't produced without heat in a MH. In addition, their smaller size would make me think they run hotter than an SE. At least as far as the temperature on the surface of the bulb is concerned. There is less surface area for the same amount of heat to radiate off.

[aquadoc]

Yes it is the same thing as if they are in the hood, but most SE are run open in a canopy, where it is the reflector, and the bulb. There are SE fixtures with fans that will run cooler than a retro kit because of the fact that the heat is being pulled awy from the surface of the tank.