De pendants - How high?

[BnG]

[All of you who run 250w de halides.

How high do you have them over the water?

From the lens I guess, not the bulb.]

 

[smiller]

[I have been running mine for almost 4 years. In that time I have varied them from 8 inches to 12 inches. It really just depends on how your corals react color-wise an/or expansion-wise. As with all reef tanks, what works for one does not always work for another. I read a thread recently about DE users raising their lights to 16 inches with great results. I have not gone that far though. Do some experimentation and see what your results are. :idea:]

 

[mmiller40]

[I started at 6 inches and after reading about the succes of others with them 16 Inches, I have moved mine to about 14 inches. I did notice better coloration and better light spread at the higher height.]

 

[mwolek]

[The higher you go the more spread your going to get, and the less it will heat the tank. As a general rule of thumb, all MH should be mounted at minimum of 10" over the tank IMO.

Another note on DE bulbs, is mount them with the bulb ends facing the front / back of the tank, rather then parallel sideways to the tank. This should get you a better light spread too.]



Edited By mwolek on 1095346856

 

[mmiller40]

@mwolek wrote:

[I can only mount parallel in the maristar. This includes the top rated DE reflector, ROIII. I would imagine that SSL would put the bulbn in the most efficent position.]

 

[mwolek]

[The reflectors of the more expensive units may compensate for this. But think about it logically, no light comes out of the ends of the bulb, so the spread would be less in that direction then the spread parallel to the bulb. Of course as I said the reflector may compensate, I'm certainly not an expert on light diffusion.]

 

[BnG]

[If perpendicular gave you enough coverage front to back, I can see how that might be an advantage.

I will set mine parrallel, I'm working on my fixture for suspending them right now. Will have them on tonight I hope.

Nice non-answer Steve... you should go into politics :laugh long:

Do you still have those Giesmanns? That is what I bought, if I'm happy with them I will hook up with you and take your used ones too. I have family in Maybank.

B]

 

[mwolek]

[

By that logic how can 2 cover a 48" tank when parallel to it? Most tanks are only 18-24" wide.]

 

[Rick]

@b&g wrote:

[Yes he does and in that very expensive Geismann light they also mount the bulbs parallel to the tank. And they could have been mounted the other way.]

 

[smiller]

@b&g wrote:

[Keith said something last week about wanting the bulbs, but not that he has tank problems I don't imagine that that is first on his mind right now. After things settle down for him I will see what he wants to do.

Which Giesemann did you get?]

 

[smiller]

[@mwolek wrote:

I emailed a good friend that is very knowledgable about lighting. Here is his repsonse:


Yes, that is true to a degree. On the new Sunlight Supply Reef Optix III, the spread is pretty uniform, but does fan out better on the long sides. On the PFO reflector (george has one), the spread is not as good and there is a noticable lack of light in the middle. If you mount the ends perpendicular to the front of the tank, you will get better side to side penetration, but not as much front to back. This is the way to do it, IMO.
]

 

[BnG]

[

13k bulbs. I bought PFO pendants.]