Last time I looked at lowes/Home Depot most of the fixtures were Pressure Sodium, Mercury Vapor, Hallogen, etc... only a couple were actually Metal Halide fixtures.
Typically you can get fixtures from Hellolights.com that are built with materials that will hold up longer in a Saltwater environment for about the same price. Typically the bulb spectrum of the lights at HD are more on the yellow end(6700) and most hobiest try to stay in the 10-14K as a general rule.
Just an opinion. I have always only used lighting systems developed for the aquarium industry. If the lights you are looking at are ok to use, the aquarium supply outlets would not carry lighting, so beware when using product not listed for aquarium use. good luck keep us posted.