metal halides

[akm]

Im recieving some light fixtures for a 75 gallon. The person im getting them from said that he made them for vho's but that you could also use them for metal halides. I know metal halides are like the top lights for growing and propagating, but i also know they put off huge amounts of heat. What would you suggest the best wattage for the bulbs would be?

Aaron

[GaryP]

For a 75 gal. I would use either 2X 175 or 2X 250 watt bulbs if you are planning on doing SPS. You'll just need to add some cooling fans to your hood to handle the heat. I've never heard of a MH compatible VHO fixture. They have totally different set-ups and ballasts. Sorry, but I can't picture this. I'd be careful on this one.

Gary

[greasemonkey]

If you mount the ballast outside the hood you wont have as much heat to deal with. Also ventilation fans will take of the rest. I would use 2, 175w on a tank that size. I have 1, 175w on a 20gal with an open tank. I used a wall pack, hung from the ceiling, and enclosed with wood paneling on the outside, and aluminum sheeting on the inside, and open above the light. This way my ceiling fan can remove most of the heat.

I feel metal halide is much more rewarding as far as coral growth, and the color quality from these animals. I see twice as much growth in my 20g with mh, than my 10g with 96w pc.s.