How high is your light?

[Supreme Reefs]

Tank is about 23inches deep and lights are 5-6 inches off the top of the water, running 2- 250watt 20k radiums and 4- t5s actinics. Im thinking thats pretty low what do you guys think? Im keeping most of the stuff mid-low anyways though.

Also i cant really make the light go any higher right now...

 

[ucantmakeme]

My tank is only 18" deep and i keep my Halides 9" off the surface. thats where the heat no longer made a huge difference in water temp. I run 2 150 14k Pheonix's.

5-6 inches seems a little low to me and would heat up the water way to much imo, even with a fan blowing on the water...

I "heard" air doesnt affect par anyways (not enough to matter anyway), so its all about heat buildup in the water.

 

[650-IS350]

18" high cube, light is 4" from the waters surface. 250watt MH 20Ks

 

[El Camaron]

as high as cheech n chong :tongue:..

LED's are about 10 inches from the top of the water and tank is only 18 inches deep.

 

[ucantmakeme]

18" high cube, light is 4" from the waters surface. 250watt MH 20Ks

Do u run a chiller? Dang, my tank would probably boil over.. lol

 

[EliteReefs]

i run 400 radiums and they are about 20 inches off the water. the tanks are 15 inches deep and corals are about 8 inches under the surface.

 

[650-IS350]

Nope, I run my tank at 76-78 No chiller. but during the summer my controller will shut off the MH when temp hits 80 and turns off T5s at 82

I have a chiller but haven't used it yet.

 

[Supreme Reefs]

Thanks for the input everyone!

Seems like most of you have the lights up higher, i have to find a way to raise mine a little bit more...

BTW any problems with the MH so low that it melts the plastic brace? Or anything on top of the tank like mesh top?

 

[650-IS350]

Dunno about MH's but when I had 8 T5s it was 2-3" from my old mesh top no issues.

 

[korndogg091]

are the MH retro or pendants? do your bulbs collect salt on them?

 

[Jeremy R.]

I usually keep my 250w lamps 16" off the water surface but am currently running them at 17.5" over my AGA 180gal (24" deep).

 

[Supreme Reefs]

are the MH retro or pendants? do your bulbs collect salt on them?

They are in a full fixture with a glass screen to protect them.

I have pics of the set up and light in my 90g thread.

 

[Troylee]

I run two 250w xm20ks overdiven 8" off the water and two 60" vhos about 6" off the water.... Over a 24" deep tank on one side and a 36" deep on the right side and keep monti caps around 32 to 34" deep and they got amazing color and growth... Need to try a acro down there...

 

[roscoe]

I have a 24'' deep tank and run 3 400w radiums 16'' from the water surface and no I don't use a chiller.

 

[650-IS350]

DE with glass protector.

 

[johnanddawn]

the general consensus has always been that:

- MH (because of the nature of a point source of light) should be placed where you get the proper spread at the bottom of the tank depending on the type of reflector and the depth/shape of the tank without too much light spill or reflectance at the surface. every reflector to tank depth/shape will require a different optimum height

- flourescent bulbs should be placed as near as practical because of their 180* reflectors so as too push as much light down without a lot of reflectance off the air/water surface interface

i'm not sure if new data from more people owning PAR meters has changed that philosophy - but it should still be sound advice for a starting point anyway

 

[Supreme Reefs]

These will get good spread, im just worried it will burn the corals and some of the plastic on top of the tank since i have a mesh top...

 

[Alpha Aquaculture]

My tanks are 8" deep and my corals are 5-7" from the surface. I run ATI PM 6 bulbs over each tank, lights affect both tanks.

Chalice tank has light 36" from the surface, par reading of 90 or so

Acan tank has light 24" from the surface, par reading of 130 or so

 

[mfinn]

My zoanthid tank is 20" deep and I have my 250 watt 20k Radium 9" from the water.
My 240 is 25" deep and I have the 3x250 watt mh bulbs 9" from the water.