Metal Halide

    Are you tired of looking at online/LFS prices and seeing that you will have to pay $500 for a metal halide over your soon to be reef tank?  I do not blame you.  That is why I have written this article, to present an easy DIY (Do It Yourself) metal halide setup that will cost you only around $100.

    The best metal halide out there is the 6500K 250W Iwasaki Metal Halide.  It can be purchased atMarine Depot  or  Premium Aquatics  and usually costs around $59.  Also, make sure to order one mogul socket for every bulb you order ($5).  However, when ordering be sure to ask that the Iwasaki be a 41R.  The R is the designation that it is for a Reef tank.  MT250DL E-39/41R is the number/letter combination that you need to make sure is on the box the bulb comes in.  Below is the structural difference between the two bulbs (the upper bulb is the 41R).

http://www.carlosreef.com/iwasaki_comparison.htm

    The Iwasaki outperforms just about every other bulb on the market (with the exception of the HQIs... which are extremely expensive).  Below you can see a chart of the different bulbs and their photosynthetic photon flux density (PPFD) and correlated color temperature (CCT).

    From the following chart you can also see the color composition of the Iwasaki 250W lamp.

http://www.animalnetwork.com/fish2/aqfm/1999/dec/features/2/default.asp

    The interesting thing about the Iwasakis is that it can be run off of a Mercury Vapor ballast.  This actually makes it run brighter and presents it as being bluer to the human eye.  The ballast manufacturer I prefer is Advance and the ballast model number is 71A3572 or 71A3802-600.  The 71A3572 will keep the lamplife for a short while longer, uses less current (4.2a to 2.5a) and has a lower voltage dropout (90v to 65v).  However, the price for the 3802 is $26 and the price for the 3572 is $50, so I usually go with the 3802.  You can call up your local  Graybar and order these ballasts.  Tell them you were told the price would be what I mentioned above and they will order it for you for that price... be warned though, it will take three weeks to be delivered as they do not have them in stock.

    Also, for anyone that would like to do this using a 400W lighting setup, the ballast info is:

Ballast Part # 71A4071 -- 1 bulb 400W (quoted $46.58 at graybar)
Ballast Part # 71A4300 -- 2 bulb 400W (quoted $77.55 at graybar)

Just please remember that a 400W ballast will run ONLY a 400W Iwasaki bulb, not a 250W bulb and vice versa a 250W ballast can ONLY light a 250W bulb.

    The next step of this is to make a reflector if you choose to use one.  A reflector rests above the Iwasaki bulb and reflects more light down into the aquarium.  A reflector can easily be made by going to home depot and buy a piece of 3'x2' aluminum.  Then paint the aluminum white (this is done to disperse the light from the bulb which in itself is a point source).  Now bend the aluminum so that the 2' part makes a curve.  A parabloid shape is best, but it will take some adjusting on your part to see what looks the best when over the aquarium.  Also, if you have dimpled aluminum available... use this instead of regular aluminum and leave off the white paint.  The following picture shows the approximate shape your reflector should be.

http://www.marinedepot.com
(notice the mogul socket at the base of the reflector)
The mogul socket will need a piece of 2x4 or something cut to mount to and then to be mounted to your reflector.

The next step is to wire your ballast to the mogul socket.  You'll need to buy some romex 12/3 wire for this, 20ft should be plenty (a 20ft 3-pronged extension cord will work just as well).  You will also need wire lugs, a 3-prong plug and a metal enclosure (such as a fuse box from home depot that is large enough to fit the ballast in and can be seen below).

    Place your ballast in your metal enclosure and run the wires out of a hole in it, such as seen above.

    You'll notice on your ballast that there are four wires coming out of it.  Two of them say COM, one says LAMP and one says 120V.  Cut the romex into two pieces, one 6ft long, the other 14ft long.  Splice the wires on the 6ft long piece.  Tie the green into the bottom single prong on your plug and tighten the screw.  Next tie the white wire into the left nub of the screw and the black wire into the right nub.  Tighten all the screws and put the plug together.  If you are using the 3-pronged extension cord, cut the plug off with about 6ft of extension cord with it and skip the steps I just listed.

    Next take the other end of the 6ft piece that is connected to the plug and strip the wires.  The white wire gets tied into the 120V wire from the ballast.  The black wire gets tied into one of the COM wires from the ballast (doesn't matter which).  Use wire lugs on both of these.  The green wire should be attached to the ballast box in some manner.

    Ok almost done.  Now take the 14ft piece of wire/extension cord and strip one of the ends.  The white wire goes to the wire from the ballast labeled LAMP.  The black wire goes to the other wire from the ballast labeled COM.  Use wire lugs on these.  The green wire should be connected to the box in some manner.  Now take the other end of the 14ft piece and strip the wires.  The white wire goes to the white wire from the mogul socket and the black wire goes to the black wire from the mogul socket.  Use wire lugs or quick disconnects for these, but make sure they are securely fashioned!  The green wire should be attached to your reflector in some manner.  (REMINDER: Only one bulb can be run off of each ballast)

    Your ballast and enclosure should look like this now...

    Screw your bulb into the mogul socket so that the nipple on the bulb is facing the reflector and it should now look something like this

Whalla!  You're done!  Plug your plug into the wall socket (stand back just in case) and you should see this....

Build this at your own risk.  If you are unsure about anything please contact myself or an electrician.

Nicholas R. Allers
June 12th, 2001

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