Help with lighting dilemma

[Dan Schmidt]

Super fan "no pun" intended . Thanks again.

[BUGZME]

Why would you want to cover the water surface? I can't think of any reason at all. Most fish don't jump Out.

[davejnz]

I couldn't agree more,lose the glass covers.Not only do they hinder gas exchange at the water surface they also block UV and some PAR.I have experimented with glass and acrylic as a UV shield for a MH mogul based bulb and SPS corals have lost color and turned brown.It is my belief that UV is beneficial to some corals and is linked to the development of some color pigments.Eggcrate is a good choice to place over the tank when acclimating to the new MH lights.I also like to use 2-3 sheets of window screen placed over the eggcrate during the initial phases of acclimation removing 1 piece a week.I prefer to mount 10" above the water surface and use bat-wing style parabolic reflectors to help spread the light.You can get a 36" spread(24" is the standard) with a single MH.It wont have quite the intensity on the edges but still enough to grow low-med light corals with.If your tank is deeper than 18-20",use 250's.I find 175's a bit dim but still effective for mixed reefs.You'll have no problems with heat as long as you use a pair of 4" fans.Another good tip is to add some passive ventilation on the top/sides of the canopy by cutting holes out and using vents(simliar to AC vents).

BTW,is your current PC setup a complete fixture or a retro?You can always scrap it out to incorporate it into your canopy but if you paid alot of cash you might be better off selling it and buying a flourescent retro that will better suit your 72" long tank(I'd use a 2x72" VHO actinic)

[tileman]

I would lose the glass top also, bad for oxygen exchange and cuts down on light penetration. If this helps here are a couple of pictures of my canopy, the fans are in the top corners.