HQI mini pendants.....Parallel or Perpendicular?

[JG]

I remember there was some disscusion a while ago about which way to mount the mini pendants for optimum light spread....anyone know what the conclusion was? Just trying to figure out what way to mount the pendants in my new 120. I have them mounted parallel in my 58 and the light spread is great, but I'm going from a 36"x18"x21" tank to a 48"x24"x24" tank and hoping not to get any shadows between the pendants.

FWIW, I'd rather have the center of the tank the brightest, and the light slowly fade as you get to the perimeter of the tank....rather then have a big shadow right in the center between the pendants.

[Ninong]

Double-ended HQI lamps are designed to be mounted parallel to the front of the tank. Your maximum coverage front-to-back will be about 23.5" provided your lamps are at least 9" above the water's surface. Closer placement results in reduced coverage.

Ninong

[PerryinCA]

I personally like it parallell, suits my tank better. I think it depends on which way you want it to spread. I have 3 MH in a 48" tank, so front to back spread was better with it parallel.

-P

[JG]

Ok, I didn't know the pendants were supposed to be 9" above the water. They're actualy about 4.5" from the water in my 58. I'll make sure they're at about that hight when I mount them in my new canopy. I'll also mount them parallel.

How far apart from each other would you suggest I mount them?

[Bubafat]

I actually emailed PFO a while ago with this question. They told me that it was made to mount perpendicular.

Buba

[Ninong]

Originally posted by JG

How far apart from each other would you suggest I mount them?

If your tank is 48" long and you want even distribution of the light, you would mount them 24" apart (center of lamp to center of lamp), which means that the center of each lamp would be 12" from the end of the tank. Since you are going with separate mini fixtures, you can adjust that a bit if you think it would look nicer to space them only 22" apart.

Ninong

P.S. - As Matt has just pointed out, the PFO mini-hoods were designed to be mounted perpendicular but the double-ended lamps themselves actually spread light in a pattern that measures 27"x23.5" when positioned parallel to the front of the tank, with the longer dimension running the length of the tank--anyway, that's what Giesemann claims on their website. That assumes that the lamps are at least 9" to 10" over the water. This is the problem Golfish is having with his HQI mini-hoods because his tank is 30" front to back and his mini-hoods are mounted only about 5" about the water; so he is not satisfied with the spread.

[JG]

Really Buba?

Hmm, now I'm back to square one again.

[PerryinCA]

I say you just sell the 250w HQI and strap a 1000w 10k right in the middle.

-Perry

[JG]

LOL Perry.

Ninong, thanks for clearing that up. I'll do as you recommended

[JG]

I'm actualy debating whether or not to add a 400w 20k Radium bulb run off a PFO HQI ballast right over the center brace, between the two HQI's.

Not sure what that setup would look like....four, 110w VHO actnics, two 250w Ushio HQI's, and a 400w 20k Radium right in the middle.

[chromis]

If you are going to go with a 400 watt 20k radium bulb then get the blueline electronic ballast. I am contemplating a 2 x 400 metal halide over my 55 gallon for sps and found that the blueline ballast runs the bulbs much better then PFO. But really you dont need a third bulb IMO.


HTH
Andrew

[JG]

Andrew,

The BlueLine ballast runs the Radium better then the PFO HQI ballast? I didn't know that.

Still considering adding the third light...not quite sure though

[golfish]

JG,
I run a 400 watt Iwasaki in a 24" PFO reflector, I also have 4x55 watt blue PC's mounted in the reflector. This, all mounted over the center brace between the two 250 watt HQI's. The reason I chose the 6.5K over the 20K was PAR. I fugured I need something that puts out a ton of light to penetrate the cross bar. I really like this setup over the 12K sunburst bulb I was using. The 12K gave off nice color but did nothing for the corals mounted under the cross bar.

Mark

[golfish]

Here's a pic with just the Iwasaki and PC's. Not bad for just a 400 watter going through 1/2" glass

[golfish]

Notice the V shape shadow. Its not as bad as the piture makes it out to be

[Nanook01]

Hi Golfish, just a couple of questions for you. I have two of the HQI over the 120g and would like more brightness right in the middle of the tank, where it is shady. Do you have a 120g tank? How much heat did that 400w Iwasaki add to the tank?? I currently have two fans in my hood, the pendants come down through openings cut into the top of the hood. How many fans do you use, or do you have a chiller??

I only have two VHO 110 watt actinics, would the 400w Iwasaki be too yellowing? I have been contemplating increasing the light over this tank for a while now. At first I thought it was good enough, but the more I look at the tank, the more I realize it needs more light, too shady. I have a problem with tough salt creep accumulating on the cross brace from the PH's, I have to razor it off daily if I want to put a light over the brace. Do you have any probs with really tough salt creep blocking the light? Tons of ??????, thanks for any replies!!

Nanook

[JG]

Thanks for the pictures Mark.

I was consdering using a 400w Iwaski over the center brace, but I just don't like the color of that bulb. The 400w Radium on an HQI ballast is supposed to put out a decent amount of light too(obviuosly not more then the Iwasaki though, but a hell of a lot more then a 400w 12k). I've seen pics of this bulb on a regular MH ballast and the bulbs is quite dim and blue, on an HQI ballast its supprisingly whiter, and more intese.

The thing I don't want though is for the tank to look white on the sides, and then blue right in the middle. I'm hopeing if I do go with the Radium, everything will blend together nicely.

I'd still use four 110w VHO actnics on the tank though. Just have to figure out a place to put that PFO ballast.....my IC ballasts mount of the back of my hood

[chromis]

The 20k Osram/ Radium lamps run a little better on the Blueline E- Ballast and you can switch to any bulb if you dont like the 20k cause they can burn anything. They are about the same price if your just buying one ballast. When you need 2 like I do then its different. Bluline eballast will probably pay for itself as it is light and therefor not $40 shipping like a PFO and will probably pay for itself in saved electric costs.


HTH
Andrew

[golfish]

Nanook01,
My tank is a 150, 48" long x 24" tall x 30" wide. Very close in size to your 120 except for the 30" wide, this is why I have the pendants mounted perpendicular. The Iwasaki added a lot more heat to the tank. I keep the house temp set around 78, I have 3 fans in the hood and a big 12" fan blowing over the sump. My temps run from 80-83. No Chiller. Oh yeah, I have a good ceiling fan in the tank room to help move out all the hot air coming from the tank. My AC runs most of the time the lights are on. Bad in th summer but good in the winter. I figure I wont have to use the heater in the winter. Like I said, I use 4x55 watt blue PC's in the same reflector to make the Iwasaki look like the 10K's.

I visited Steve Tyree yesterday, he uses the 20K bulbs on all of his tanks. The color looked a little more white then I expected but its kind of hard to tell since the bulbs are mounted so high and the tanks are all open top.

It looks like I'm going to be able to try out a 20K bulb and 400 watt HQI ballast. I think I'll replace one of my mini pendants with it.


Mark

[JG]

Mark,

Were you impreesed at all with the 20k at Steve's place? Does he run his on an HQI ballast?

I think the bluline ballast is out for me because I was reading you can't use x10 controllers with that ballast. I use an x10 controller for all my timers.