retrofit lighting questions

[cinnamongirl]

I'm looking to build a wooden canopy and a get a retrofit lighting system for it... i'd like to have Twin 25W 10K Metal Halide, 1 Aqua Sun and 1 Actinic Sun VHO bulbs. Plan on doing the sunrise/sunset effect as well.

Im not sure the best way to go about this. I've seen retros with this combination of lights available in one, but they have one big reflector around the entire thing. Is this ok, or should i have an individual reflector for each and purchase them separately?

We plan on leaving the back open and two fans on the ends. Can I have it covered with only the back open, or should the top be open also? I'm not too worried about heat into the tank itself, my house is nice and cool. But should I worry about the MH catching the wood on fire if it is enclosed on all sides except the back?

How far away should the lights be? I'm thinking 7-8" from the waterline. Should I have a glass cover over the water, or leave it open to the air?

My tank is 75 gallon, intended to be reef.

Thanks!

 

[Juck]

I have a 75 with 175 Ushio Halides and mine are mounted to the underside of the wooden hood in individual reflectors,, the wood gets warm but not hot. They are about 8 inches from the surface of the water. I think with two fans blowing into the hood you will be fine,, no need to have the top open. I only have one fan and my water temp is 80 pretty much all year round.

A glass cover is not necessary but will probably cut down on evaporation and perhaps heat transfer to the water,,,, but you have to keep it really clean.

I'm about to upgrade to 250's myself. I don't think you're going to need any daylight vho bulbs,,,, 2 x 250w is all the white you're gonna need, and then some,,, I'd stick with one or two actinic VHO's for your sunrise/set thingy.

Good luck

 

[qwiksilver]

Juck is right, 2x250 10k's are gonna be plenty white, go with the two actinics for VHO's. Open or closed is really a choice of preference. If you want less hassle, go open. Just make sure you don't keep a shark or some big fish that does cannonballs into you tank and splashes the bulbs, as at 600F, (I was curious and measured a set of 250W bulbs one day) they will shatter in a heartbeat. Had it happen to me once, I was changing a Halide outside (i am an electrician) and some snow slid in behind the cover and the bulb blewup.... pretty amazing flash, saw sunspots for a looooong time.