Metal
halide bulbs are available in several different Kelvins,
or color tempertures. 6,500K bulbs are a yellow-white
color, 10,000K bulbs are a crisp pure white color, 13,000K
bulbs are white with a very slight blue tint, 14,000K
bulbs are white with a strong blue tint, and 20,000K
bulbs are a deep blue tint. Metal halide bulbs come in
several wattages from 70, 100, 150, 175, 250, 400, and
1,000 watt.
Selecting the proper wattage metal halide
system depends upon the depth of the aquarium as well as
the type of corals beign kept in the aquarium. 150 and
175 watt systems can be used on aquariums from 16" to
20" depth for corals requiring medium to high light
levels and for aquariums from 18" to 24" for
medium to low light level corals. 250 watt systems provide
adequate lighting for 18" to 24" deep tanks with
corals that require medium to high light levels and for
aquariums that are 22" to 30" in depth with corals
that require low to medium light levels. 400 watt metal
halides provide the proper lighting for aquariums 22" to
30" with corals that require high light levels and
30" to 36" deep tanks with medium to low light
level corals. 1000 watt metal halides provide tremendous
lighting that is adequate for tanks 32" to 42" with
corals that require high to medium light levels and for
tanks that are 40" to 54" deep with corals that
require lower light levels.
The following manufacturers produce high
quality metal halide bulbs:
