Suspended Lighting or Not?

[NaanDu]

I see so many people with their lighting suspended anywhere from 6-18 inches or so from the top of their tank. Is this necessary? I understand how it can provide a more even spread of light but are there any benefits beyond that? (With the only con I can think of being a reduced par rating across the tank)

I have a bar light with the brackets that sits directly on top of the frame of the tank. Would it be better to suspend even this kind of light? My corals seem to be growing okay, but I also have all my rockwork stacked in the middle-ish of the tank and almost all my corals are on or in that rockwork with the exception of my leather corals and a huge ball of gsp being on the sandbed. I just want to make sure my corals are going to grow the best they can.

It's an Aqueon 20long tank so it's fairly shallow. Just curious about everyone's input.

 

[Mr. Mojo Rising]

droplets of water splashing up at the light can break your light, I would not want my expensive lights so close to the water.

 

[NaanDu]

droplets of water splashing up at the light can break your light, I would not want my expensive lights so close to the water.

I guess I should have specified that I have a glass top on my tank.

 

[PharmrJohn]

It depends on what kind of protection you have over the LEDs. If they are sufficient to thwart saltwater, then you're cool. You have a glass top so that issue is minimized anyway. I'm gonna do the same thing. Glass top and plop them on my aquarium.

 

[Oldreefer44]

Couple of things. All depends on the lights. Some are fine close to the water surface and some not. The manufacturer will quite often give recommendations. Suspended lights can be much easier to move out of the way. Some people even have a system to raise and lower them so that it gives easier access to the tank.
Also, glass tops are generally discouraged as they can inhibit gas exchange at the waters surface. This can effect PH etc.

 

[KrisReef]

I like suspension set ups that have a motor to position the lights and move them out of the way easily.

Otherwise, a light over a tank has to be held in place somehow, and there are many solutions people use including suspending them.

 

[bobnicaragua]

Higher lights make it easier to reach into the tank.

 

[Uncle99]

You posted your corals are doing OK.
Why change that?

 

[oreo54]

I see so many people with their lighting suspended anywhere from 6-18 inches or so from the top of their tank. Is this necessary? I understand how it can provide a more even spread of light but are there any benefits beyond that? (With the only con I can think of being a reduced par rating across the tank)

I have a bar light with the brackets that sits directly on top of the frame of the tank. Would it be better to suspend even this kind of light? My corals seem to be growing okay, but I also have all my rockwork stacked in the middle-ish of the tank and almost all my corals are on or in that rockwork with the exception of my leather corals and a huge ball of gsp being on the sandbed. I just want to make sure my corals are going to grow the best they can.

It's an Aqueon 20long tank so it's fairly shallow. Just curious about everyone's input.

You need to understand the physics of the lights. Many led lights have 90 or even narrower lenses (Orphek bars now comes w/ 70 degree standard)
A single led lensed 90 degrees 12" off the water will throw "spot" of 24" in diameter.
Your lightbar is "likely" to have 120 degree leds..At 2" it spreads to a 7" diameter spot size.

"Best practice" is to try to train all the light output to the surface of the water with little "spill" outside of that.

There are other things to consider like height also helps blend colored leds and it also evens out the gradient of the par from top to bottom and can better fight shadows..
Narrow lens, high height.

Height does decrease par levels though..especially if you overshoot and have a lot of light spill.

Anyways this is a brief "tutorial" for you.

How High Should I Hang / Mount My Aquarium Light? - ATI North America

One of the most frequent questions we get is “How high should I hang my light over my aquarium?”. And it’s an important question to answer. Mounting a light at the proper height can make a big impact on your coral. Mounting an aquarium light too low creates shadows and less light gets to the...

atinorthamerica.com

In the mostly "old days" height adjustments were one of the few methods of "dimming"..