Metal Halide remains the brightest, highest output light source for the marine reef aquarium.
A decent Metal halide set up has never been cheap and various other systems such as T5 and LED based lighting have come along to challenge metal halide by offering better value - yet none have succeeded in equalling metal halide’s very high output, very penetrating light which produces unparalleled growth in photosynthetic Corals and other, similar invertebrates such as gorgonians, polyps and macro algae.
The point source nature of metal halide bulbs means that when suspended above the aquarium, a very natural rippled appearance is possible with natural shadows created by water movement. Some experts have even suggested that this effect improves Coral health and enhances photosynthetic efficiency.
Metal halide bulbs are largely white in colour - even the latest 15000k bulbs are bright white and benefit (in terms of appearance at least) from the addition of some blue light via marine blue or Coral fluorescent tubes.
All Aqua One metal halide luminares have a pair of high output Marine blue PL lamps per metal halide bulb. This gives a very pleasant light with an excellent ‘under the sea’ colour balance which maximises Coral fluorescence and encourages Coralline algae growth, while retarding nuisance algae growth.
For many Aquariums a luminaire featuring a number of smaller metal halide bulbs is superior to a fitting featuring one large 250 or 400w bulb. The light source is therefore less concentrated and more usable to a wide range of Corals. Relatively few Corals are happy under direct light that is very, very strong so think twice before fitting large bulb (250-400w) metal halide light over an aquarium of average depth.
If you change your metal halide bulbs once per year your Corals will enjoy consistent spectral output and your luminare will last for many years. The accompanying marine blue PL lamps should, in common with every fluorescent tube be changed every six months.
Though metal halide fittings are never cheap they do represent the best in aquarium lighting and are therefore a great investment.