Double-Ended MH bulbs

[ALRHA]

I was originally planning to have a 5' hood inside my canopy with two 400W MH bulbs and actinics. I have since decided to put the lights above my canopy to keep the water from heating up. I was a thin light so that it doesnt show so much and look ugly.

1) Looking at online retailer sites, it seems that the double-ended (HQI) bulbs are generally in thinner fixtures. Is there any disadvantage to using these compared with the single ended bulbs? why would anyone get the single ended then if the HQI are thinner?

2) I am having trouble finding a 5' hood with the amount of light i want. I cant find 400W HQI bulbs, so i will probably have to go with 4x250W bulbs - and no actinics since they will be pendants. Would two 10k bulbs and two 20k bulbs be just as good? What is the need for the bluer lights anyway? why are they considered nicer? I happen to like the look of the white lights and would put four 10k bulbs. would that be a mistake?

3) laslty, if i am putting four 250W bulbs as opposed to two 400W bulbs, am i losing out on light at the bottom of my 30" deep tank b/c the 250's are not as strong, or would it be pretty much the same thing?

[liv]

we can definitly start another debate on this....lol, but most will agree that a 250w de is about the same as 1 400w se.

the problem with de's is that they do not have any uv shield built in. So you have to by a pendant or make yourself one using glass. they are also a bit more fragile.

Ivan sells the pfo pendants for ~150$ i believe.. you could get 4 of these. they are great pendants with the main reflector emitting close to 98% of the light sent to them.
normal reflectors are ~45-70%.

the only thing i could think that would be a disadvantage would be when you need to replace all 4 bulbs instead of 2... the cost of the bulbs, ballasts and pendants.

[CableGuy]

I have also heard that you have to change HQI bulbs more often then SE bulbs.

Blue lighting is for personal appeal, I like the look of 10K, so I have 3 X 400watt 10K XM bulbs on my 220 gallon and I really like the look of them. Plus 10K bulb gives out more PAR than a 20K bulb does.

If you like the look of white with just a hint of blue, you can go with 13K bulbs. HTH

[ALRHA]

oh, cool. i didnt know that a 250W DE would provide as much light at a 400 SE. So i guess i would only need 2 or 3 250W DE bulbs for my tank (60x24x30). Perhaps i can put two 10k with a 13k in the middle. From what i've understood, the bluer lights make the coral colors look nicer.
Now I have to decide if i want a hood or pendants. Any advantage to one over the other here? The hood may be easier as it is just one piece, but with the pendants i know I can always add another if i wanted to, and i am not limited to what is offered in hoods my size.

[john rock]

250w DE do not provide as much light as the 400w. I know I know, there were tests!!! yes but those tests did not use a shield on the DE lamps plus the internal refelctors that come with the DE lamps do not spread light the same as a SE lamp with a good reflector. SE lamp setups have better spread by far. there have been tons of debate on this subject. If you raise the DE lamp pendants up to say 12'' then you'll get the same 2 foot x 2 foot spread but you just lost a toin of intensity. any tank over 24'' deep IMO need 400w SE lamps if you want good lighting. especially if you are going to run 10k and up! when they make a 400w DE then I might try them.

[ALRHA]

I am looking into this spacelight. You think it will be good for my tank? i dont know what good alternatives there are to this. If needed, I can just buy two of these and place them side by side (overlaping 3' in the middle and each a foot out to the end).
I can get them for $840 each, and each will have 2x250W 10k and 1x150W 20k.
http://marinedepot.com/md_viewItem.asp?idproduct=AQ1561

[ALRHA]

note: i dont mind limiting my SPS to the top 24" and putting LPS and softies on the bottom 6".

[ReefSalt]

First of all I used 400w Radiums ,and now I use 250w DE`s.
There is no comparison for the spread of the 400w they cover a larger area no doubt about it.

Alrha,
if your looking for a unit Aquaspace is a good one but on the expensive side you can pick up a 2 x 250w with a T5 actinic setup for less than the Aquaspace and thats in Cdn $$.
I prefer T5 over a center Actinic P.C or 20K DE option,because the coverage is better with the T5`s.

[ALRHA]

but i like that the ballasts are in the fixture already (less wires, less mess) and that it is only 3.5" hight, so it wont show over the canopy so much. the others are at least twice as high, and dont even have internal ballasts.

[ReefSalt]

here is a picture of what I am talking about.They are 4" high 10" wide and available up to 48"

http://aquariacanada.com/PhotoPost/showphoto.php?photo=827&password=&sort=1&cat=500&page=2

[ReefSalt]

Your right the ballast are external I prefer them that way personally,If something happens I can swap the ballast. when it`s internal you got to send away your whole cover so they could see it and repair it and they do stand more of a chance of having a problem since everything is enclosed where there is alot of heat.,what do you do in the mean time? Back to the dark ages;)

[ALRHA]

well if i get two of them, then i will still have the second one running (unless they both break at the same time). I dont plan on it breaking, and if it did, i would borrow another light to use in the meanwhile.

[ALRHA]

and i think they look a lot nicer, which is a big part of it for me.
i am just trying to think if i should get one or two.

[ALRHA]

I can also get them with 2x250W 10k and instead of a 150W 20k bulb, i can get it with 2 PC bulbs. would that be better as it will distribute the blue more evenly? or should i stick with the 20k MH as it will still be a stronger light?
http://www.premiumaquatics.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=AM-75368&Category_Code=Aquamedic-H

[ReefSalt]

Thats a better solution with the P.C bulbs the light will be distributed better.And if I recall corectly the Aqua-Medic units come with AB (Aqualine Bushke)10k bulbs so your ahead of the game they have a very nice color to them in DE bulbs one of the best.