Re: HPS

[Bill Wichers <billw at waveform_net>]

Richard J. Sexton wrote:
>There's no such thing as a cheap metal halide ballast. Mercury and HPS
>can be had cheap as outdoor safelty lighting.

There *is* such a thing as a cheap MH ballast, but you have to buy them at 
electrical supply places and not aquarium supply places. The primary market 
for MH is not aquarium lighting, but rather is *interior lighting* of 
*large* areas (warehouses and the like). You'll see MH lighting used in 
places like Home Depot and Costco to light their large stores. MH is also 
growing in popularity for security lighting since many people can see 
better in the more balanced light spectrum it provides. MH ballasts bought 
wholesale are priced similarly to HPS ballasts, which makes sense 
considering that they are very similar in construction.

MH light fixtures can be had cheap but are typically called high bays or 
low bays, which are commercial lighting fixtures and the "hi" and "low" 
parts refer to the height the lights are to be mounted at (they are focused 
differently based on their intended mounting height). The fixtures are 
rather large though, so if an aquarium fixture is desired it would be best 
to use the high bay for parts and use a different reflector. You can think 
of a high bay (or low bay) as a very large pendant-type fixture.

         -Bill
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Waveform Technology
UNIX Systems Administrator