Metal Halide and T5 Retrofit Questions

[BBP]

I set up a new 135 gal reef tank about a year ago and installed four VHO actinic and florescent fixtures in a custom hood I had built for it. All told, I'm running about 786 watts total. I installed four fans and made some ventilation holes in the hood but I've had temperature problems since the beginning. One critical mistake I made was mounting the ballasts in the lid of the hood as well.

I am planning to completely redo the lighting. The two main goals I have are to eliminate my overheating problem (temps are running 82-84 preventing me from adding any invertebrates) and to improve the overall lighting in the tank with metal halides. I have couple of challenges in that the tank is freestanding and thus I had the hood built so it is enclosed on all four sides. The aquarium is in the middle of a room, so it is darned near impossible to install pendant lights.

Here's a couple things I was thinking about and I'd like some feedback on any issues you folks might see in the plan:

I plan to cut three holes in the lid of the hood (It's solid oak) and mount three metal halide fixtures over the top of the holes. This would put the bulbs about 8" from the glass lid. Theoretically, if I could find the right fixtures, I could ventilate the MH fixtures through the tops. Problem is, I can't find the fixtures I need.

I also plan to replace the other lights with about the equivalent wattage that I have now (786) with T5HO, and move all of the ballasts to the cabinet underneath the tank. I'm in hopes that this will provide me with extra space I can use for some additional cooling fans. I've looked at the Nova retrofit kits for the T5HO and they look like they have what I need.

Any feedback or advice is appreciated.

Thanks
BKB

[BBP]

bump

[jag1979]

you wont need to match watt for watt w/ mh and t5's v. vho if you want the same amount of light. Mh's and t5's are almost twice as powerful as vho's at the same watt's. That is assuming you use good reflectors which the nova does not have. You should look into something w/ individual reflectors like the tek t5 fixture.

[jag1979]

Unless you really want mh's you might consider replacing the vhos w/ t5 only. The best thing to do IMO is get some icecap t5 retro kits (reefgeek has a good selection). You wont need as many watts which will cut down on the heat. 6 or 8 x 54 watt t5's should be plenty to keep anything...what are the dimensions of the tank? If the 54 watts are drivin on icecap ballasts they overdrive to 80 watts so 6 should be plenty.