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Re:Lighting for a 100G "long"

Hi Karen,

Being an old salt I know a little about the Metal Halide type lighting
(although I've never had plants set up using MH).  For reef type tanks
(where light is as important to corals as it is to plants) one MH bulb per
2 feet of tank length is the standard (since they are a point source of
light as opposed to a diffusion of light from flourecent tubes, so the
further you get from the center of the point source of light the weaker the
intensity).  A noted coral aquarist Dana Riddle has done a lot of research
with MH bulbs (PAR & PUR) and he found that to be the proper distance
without over laping with other lights.

For bulbs that are suitable for planted tanks there are these formats:
5500K 175 watt USA
5500K 400 watt USA
6000K 175 watt USA
6500K  70 watt Iwasaki (Japan) (I've never found a source but they exist)
6500K 150 watt Iwasaki (Japan)
6500K 250 watt USA
6500K 250 watt Iwasaki (Japan)
6500K 400 watt Iwasaki (Japan)

Also I've heard of 1000 watt versions of some bulbs but I've never found them.

Mr. Riddle has used and recommends the Iwasaki bulbs particularly the 400
watt bulb (because of its watt/par ratio, I think you can find this in a
past issue of Aquarium Frontiers, I think the printed edition) because he
has found that the lights spectrum shifts slowly and the bulb lasts for up
to 2 years (useful life) which means for planted tanks it will last longer
(because it shifts to the yellow/red spectrum, people say the bulb is
greenish when new).

As for the height of bulbs is usually between 6-12 inches above the water
surface.  Many people use UV sheilded glass or plexiglass to protect
against UV and exploding bulbs (check Deja News for Corallife 10000K bulbs,
 they had a tendency to explode, I think that they are off the market now).
 To make the viewing of the tank easier, you can get the MH in a Pendent
the consentrates the light downwards (you can go to www.reef-fanatic.com in
the lighting section to see what a pendent looks like).  Pendents look nice
and they allow greater cooling for the bulb.

Some annoying things about MH is that the ballasts used to drive the bulb
is big, generates a lot of heat & sometimes hums (these are coil/tar type).
 New electronic type ballasts are small, efficient, cool, and can drive 2
bulbs (check out the Ice Cap ballasts on the webpage above).

If you have any further questions about MH please feel free to e-mail me.
I hope this helps,  good luck,

Sincerely,
Victor Eng
Vancouver British Columbia, Canada
engfam at axionet_com

>Hi folks,
>
>I'm getting ready to set up the 100G "long" tank that I "inherited" last
>summer.(finally)
>
>I'm considering my various options as far as lighting is concerned.
>While I'm a big fan of T-8 lighting, the 6' length of this tank makes T->8
lighting a bit tricky.  The better color temperature bulbs seem to be
>available only in the 4' lengths.  This means I would either have to
>stagger the bulbs and mix them with 2' bulbs, or live with color
>temperature bulbs that are not really to my liking.
>
>A pet store near me can get me a reasonable deal on a 6' VHO fixture >that
would do the job, but I'm also considering an open top tank with >MH's,
since I love the look of open top tanks, and I _think_ my kids >are past
drowning age.<g>  My questions are:
>
>1.  The tank is 18"x18"x6'.  Anyone else working with this size tank?
>What are you using for lighting, and what do you like/dislike about your
>setup?
>
>2.  I'm assuming that with this size/shape tank, that I'd want to go >with
2 175W bulbs?  
>
>3.  How high would they have to be hung to avoid burning emergent >leaves?
>
>4.  This tank is going in my livingroom, and I want people to be able to
>sit comfortably nearby without being blinded by the light.  Any
>suggestions on the best way to keep the light headed into the tank and
>out of the rest of the room?
>
>Karen Randall
>Aquatic Gardeners Association