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!

[Geoff]

all of the things you listed each have their merits. i went with complete DIY pieces. my VHO's were a retro-kit. the MH's were parts i have found.

the wood will not catch fire unless the bulb is touching the wood, or very close to it. i would/have a reflector on the MH's. i do not have reflectors on the VHO's since they have them internal (if you get URI bulbs).

do not put covers over the tank. this will trap in a lot of heat and will cause problems. 8 inches is a good height above the water line, more is better, but 8 is good.

since you have MH's i would just use actinics for the VHO's. these are for giving POP to the corals and for removing any yellow cast that the lower K bubls could be giving to the tank.

the more open the canopy can be the better. you want to bet the heat out of the canopy. make sure the fans you get are at least 4" fans.

G~

[wanareef]

I use the spider reflectors that reeffanatic has and have not problems having the reflector right up to the top of the hood.

As Geoff mentioned, get actinics to supplement the "yellow" in the lights. Have them on timers as well for your sun up/down. Put your fans on a times as well. Same time as they go on and maybe an hour after the MH's have gone off. This works for me. And have the fans blow in, this helps in the evaporation and gives a little onger life on the fans. (salt air + metal = corrision)

I DIY the lights and think I have saved a lot doing it myself - kind of helps to be able to save more $$ for corals. heh heh