20K MH: DE 250w VS. SE 400w

[Macbeth417]

For my 110g tank I currently have 3X 250watt DE pendants running 10K bulbs, which is more than ample for a 60" long and 24" deep tank. However, I would like to switch the two outer bulbs for 20k bulbs and am trying to wiegh the impact of reduced intesity on overall quality of light. Normally, with a mogal setup, I would go with 400watt ballast/bulb configuration if I was going to run a 20K lamp, however, with the increased intensity inherent to the DE/HQI setup I am wondering if I can use a 20k 250watt in a DE and still have it be relatively comparable to a 400watt mogal light. I will do some digging when I get home and hopefully Sanjay or one of the other lighting mongrals has written up a study that will provide me with information to this effect, namely Par/lux or lumens of 400mogal 20k and a 250watt DE 20k.

Any ideas, experiences or opinions would be greatly appreciated.
Should I sell my De 250watters and replace them with 400watters? Can I use my current lighting without any major disparity in quality between a mogal 400w 20k and a DE 250w 20k.


Okay, I repeated myself and rambled enough. Now it's your turn, have at it.

-Erik

 

[Macbeth417]

NOTHING?

Well that's what I get for asking a lighting question... guess it's time to hit the books. I'll post if I find anything interesting.

-Erik

 

[jlehigh]

Hey Erik,

My understanding was that the 20K DE's were not as comparable to the 400's.. You know you could probably do two 400 watt DE's at 20K and get the best of both worlds.

I would definately reference Sanjay's articles. My 400 watt DE's aren't much brighter than mogul 400's but the spread seems to be very good.

 

[mojoreef]

Eric I would do the 400 watters. You will just end up eating through to many bulbs if you go the 250 de. Rememeber these bulbs were designed for a diferent power source so you are already overdriving them just using normal balasts. once you go hqi your doing it even more and will reduce the life of the bulb. You can still do it, but it gets more pricey


Mike

 

[Solov]

Wait a minute...

Can you alaborate on "designed for different power" and "overdrive" parts? Why aren't they used in their designed way?
Is this true to all DE bulbs?

I'm very confused.

 

[Ed Hahn]

I think Mike is saying it is cheaper to run two 400 watt bulbs compared to 3 bulbs. I could be wrong. I am also wondering which ballast Erik is using to drive his 250 DE bulbs. I hope someone can set me straight..Im confused at how he could run a DE bulb without a HQI ballast...Teach me something someone please.
Ed

 

[Macbeth417]

I decided to stick with my 250DE pendants and am going to Give the hamilton 14k bulbs a try.

-Erik