Metal Halide

[Phatboydime]

When I hear of you guys using metal halide lights for your SW tanks. Are these what you are referring to?

http://www.bulbstoreinc.com/images/Metal_Halide_Lamp.jpg

I happen to have two sockets and ballasts for these puppies laying around in my shop. Could I use a 400w version of this light, and some cheap fluorescents to have a reef tank? Under a DIY canopy of course.:help:

[Devilish]

Yeah, there are to types of MH. There are double-ended ones and single-ended, like the one you pictured. I currently use a 400w MH and that is all that is needed. I have been told that this may be over kill, but the reason I use this high of a wattage is because my tank is 24" deep and the light is 20" above the tank. Depending on the size of your tank and what type of corals you want to keep, 400w may be fine or it may be too much. You definitely will not need any fluorescents imo. I use a 20K bulb which gives a nice blue hue, my preference, but you may like a yellower tank and go with a 10K, but this will send your PAR soaring. Also, be prepared for the amount of heat this will put out. Temp of tank will be affected by the light. I usually run a box fan between the light and tank during the warmer months. But this then leads to increased evaporation. Hope this helps.

[Phatboydime]

Yes that helps. I could not find out what the K value of the bulb I was looking at was, but youve steered me in the right direction.

Edit. I just found out that the bulbs I was interested in are 4,000K only...bummer.

[Ace25]

Bulbs are easy to change out. Most bulbs in warehouse/street light fixtures are not designed with PAR in mind, but you can easily buy a bulb that is made for this hobby and use the same ballast/socket.

I just switched from 10K w/ 4 T5HO Actinics to a 20k w/ the same actinics.. first impression, I don't like the 20k at all, but I know I have to give it a few weeks to burn in the bulb before I can get the true color of it.

6 month old XM 10k on left, brand new (10 minutes old) Radium 20k on right.
http://farm4.static.flickr.com/3441/3256227789_ef28551ced_o.jpg

[Phatboydime]

I prefer the more natural light on the left. The 10k. (wanna mail me your old bulb..lol)

The ones we have at my work only go to 4,000k. Im guessing that is going to be very yellow.

I was wondering though. If I used that in conjunction with two 40w daylight flourescents, and a 48inch black light, would that make the light appear not so yellow?

[Devilish]

The problem with using something with that low of a temp you will probably be fighting a major algae problem. I believe the use of black lights are bad for tanks. Not positive, but I remember reading something about them frying the tank. IMO, a single 400w MH will be more than enough on your tank (if not too much, not knowing the size) and you should purchase a bulb specifically for aquarium use. You may want to go with a 15K bulb, best of both worlds, warm for growth and cool for appearance

[Phatboydime]

Thanks for the info...I didn't realize I hadn't posted my tank size. Its a 55 long. 48x12x18. I was planning on using a 250w for this tank. Under a custom canopy with computer case fans on the top at either end. One intake, and one exhaust, to keep the temps inside the hood down.

The only reason I am suggesting using some tube lights with the MH like I posted above is so there isn't a bright spot right in the center of the tank.

So build a canopy, use my ballasts and sockets, and get an aquarium specific MH bulb with a Ktemp of 10-12k. I really don't like the blue hue with the higher rated bulbs. Use a couple daylight fluorescents just to even out light distribution. Pop in a couple led pods for night viewing, and walla...the perfect low budget lighting system. Right?

Sound good?

Oh sorry for being a bother, but could you point me in the direction of a place online that sells aquarium specific MH bulbs with the mogul base Im looking for?

[fsn77]

A single MH lights an area of roughly 2' x 2'. On a 4' tank, two of them would be advisable to get full end to end coverage. Fluorescents could be used to acheived more of a color balance, but I doubt there's enough room to install enough fluorescent bulbs to offset the bright spot in the center of the tank that a single MH would create.

Some online places to shop for MH bulbs include...
www.hellolights.com (http://www.hellolights.com/)
www.reefgeek.com (http://www.reefgeek.com)
www.aquariumspecialty.com (http://www.aquariumspecialty.com)
www.marinedepot.com (http://www.marinedepot.com)
www.drsfostersmith.com (http://www.drsfostersmith.com)
Most online marine aquarium retailers that sell lighting supplies sell mogul base MH bulbs.