Re: METAL HALIDES
Scott Corbeil wrote:
> Approximately six months ago I made the leap to a 150 gallon 2ft deep.
> how far above the tank should I suspend the light.
This will vary depending upon how many watts of lighting you have and
what your algae situation is like to begin with. Generally, you put
the lamp higher at the start until the plants get the edge on the algae
and then you can lower it later one. If you don't over power your tank
and use a single 250 watt system, you'll probably be able to drop it
to about 10-12" from the water. That gives you enough room to get
into the tank for ease of maintenance which is a big plus for me. It
also depends on the length of your tank and the geometry of your
reflector. I have no problem casting light out to the ends of a 4'
tank taking advantage of reflection from the two end walls of the
> how many watts is recommended for this size tank?
The bare minimum is probably 250 watts but it depends on what you can
get your hands on. If you can get a ballast & lamp in the 300-500 watt
range and you want to go with HIGH intensity lighting I'd say go for
that. The FAQ has a section on calculating watts based upon tank
dimensions for low to high light plants. You can probably get away
on the low side since your tank may not be as densely planted as a
smaller one and still have a very pleasing look. Not crowding the
plants makes them much happier too.
> this tank is in my living room, does anyone have any suggestions on
> how to install such a system while maintaining aesthetics.
My lamp fixtures are painted flat black on the outside. They are
the deep parabolic reflector types and are suspended from the ceiling
via chains attached to a butterfly hook. The flat black looks nice
and has the advantage of radiating heat build-up away better than
other colors. A shiny metallic surface reflects well but radiates
very poorly; that's what you want on the inside surface.
> is it better to use two smaller bulbs instead of one large one?
The advantage is you can get a more uniform lighting. The disadvantage
is it may cost you more than twice as much since lower wattage lamps
and ballasts may in fact cost more since they are less commonly used.
I find a single pendant works fine even on a 1'x4' tank. Your dimensions
are probably better suited to a single pendant than mine. Each lamp
requires its own ballast and fixture. I'd phone around to all of the
hydroponic outlets in your vicinity for prices especially those guys
who have access to used equipment like ballasts. Always get a brand
new bulb. There are lots of parabolic reflectors in use for industrial
applications. My supplier has a jobber build aluminum enclosures for
the ballast and wires the rest together using off the shelf parts. A
system like this can be put together for ~100 US$. Buying retail
kits can double or quadruple that price. Don't buy from an aquarium
outlet unless $ is no object. The systems I've seen there were
under-powered to boot.