How High Should Mh Lights Be Above The Tank?

[devaji108]

Ok I am getting MH 2x 175 HQI for my 90 gal. reef today!

The question is how high should they be above the tank??
and how many hours should I run them. I am using 2x 65W 12k & 2 x 65w acts. PC
any feed back on integrating the new light to the tank?
If they are on to much will it cause a algae bloom?
Thanks
~Deva~

 

[dejaco]

The hieght you set the halides above your tank depends.
Is it an open or pool system?
If you have a canopy do you have glass tops directly over your tank?
If you have a canopy how tall is it?
Information needed to answer your question correctly.

 

[devaji108]

thanks for reading my post!
ok yes I have glass over my tank
yes I havea canopy the top sets about 6"above the tank.
and you lost me on the other question??

 

[thegrog]

6" is still a little close to the water surface. MH lights should be 8-10" above the water surface.
Loose the glass top if you have a canopy. The glass will not only absorb some light, but will cause your tank to get warmer with the lighting.
So, to answer your question, get the lights as high up as you can with your canopy.

 

[jayc]

Yea, I've always heard between 8-10 inch's.
Josh

 

[lepete]

The bottom of MH bulb is about 4" to the surface of the water. I dont use a glass barrier. The bulb is already at the top most position for my canopy. I dont have any jumpers (eel, gobies, etc.). I know ... I am just waiting for an accidient

 

[oceana]

Originally Posted by lepete
The bottom of MH bulb is about 4" to the surface of the water. I dont use a glass barrier. The bulb is already at the top most position for my canopy. I dont have any jumpers (eel, gobies, etc.). I know ... I am just waiting for an accidient
to close if you ask me. heat/ventalation/water hitting bulbs. all of those thing are possible problesm with the bulbs that close.

 

[devaji108]

thanks every1 for the great feed back!