MH Pendant Height Recommendation

[Turd Ferguson]

So the 250W Cayman Sun (14k Hamilton) arrived today.

It will illuminate a 40G Innovative Marine EXT, any recommendations on a good starting height ? I’d prefer it low say 10” to reduce light spillage but I’m guessing it needs to be higher. 12 years ago I ran x2 150W over a 75G ( about 6” from waters surface), and had no issues with heat,...but it was a Coralife fixture with so so reflectors. This sucker emits supernova in comparison.

Must admit, I’m a little concerned I might cook the tank, it’s the smallest volume of water I’ve ever had and might transition it to a 60G cube but I’d prefer to run it on the 40G

Any advice is appreciated. I’m also guessing I’ll need to place the euphyllia at the bottom of the tank. ‍

 

[montethemoster]

I would recommend getting a par meter, and I also agree that you will likely want to mitigate the heat on that small of a volume.

I personally use a 250w radium in a similar reflector and see increases of a couple degrees on a 93 cube with 40breeder sump over an 8 hour light cycle.

 

[A. grandis]

12" off the water surface for like 2 hours a day the first week to start.
Then you increase time little by little.
You can do 3 hours the following 1 or 2 weeks, then one more hour...
Final photoperiod will depend on having supplementation or not, types of corals you have there, etc..
I have my Spectra with 4 X 54W HO T5s ON for 9 hours and 2 X 250W halides for up to 5 hours over my 75gallon zoanthid tank.
1 X 250W for like 6-8 hours /day over your 40gal will be great. Just go slow...
Adapt the new corals to the light carefully, specially if they are coming from those tanks lit by blue LEDs.