VHO Lighting ?s, proper cooling and bulb height from water

[Jackson919]

Hello,

I have a standard 55 gallon tank that I'm building into a reef. It has the standard dimensions of 48" x 13" x 20". I have purchased the Ice Cap 660 retrofit kit with 4 110W ouput VHO bulbs that I'm putting into a DIY lighting hood. Within this hood there will be the 4 VHO tubes with the IC 4" variable speed cooling fans at either end.

My first question is high high do I want the tubes to sit off the water, is there a general rule of thumb depending on the critters, the height of the water column or does it not matter as long as the bottom of the tank is getting the light? I am thinking around 6" off the water line??

My second question is how do I want the air flow pattern to go. Meaning, should I point both fans at each other which will push air into the canopy at both ends or should I have one fan pushing air in and the other sucking it out, or both fans sucking the air out, etc. I've set it up to have one fan blowing air in and the other sucking it out, I also drilled 4 2" holes along the top to vent the hood. Any other suggestions are welcome.

Any help is appreciated, thanks.

 

[ChrisRD]

6" from the water sounds good to me. Some set fluorescent lamps even closer but you may have to wipe the salt creep off the lamps more frequently if you do.

If the canopy is not vented I would have one fan blowing in and one blowing out. If it's vented somehow, open back, etc., I'd have them both blowing in.

JMO & HTH