Newbie Question

[Aquattro]

Welcome to Canreef!! I've never heard of a 500w MH bulb before....are you sure on this? You'll need to find out the color temp of the bulb (this is a number with a k after it...5500k, etc).
You may have to do a search on a part number or something to find out that info, unless you still have the original box it came in. Also, depending on what type of bulb it is, it may have already gone thru it's useful life. Bulbs last about a year on average.
Post the info you've got tomorrow and we'll see what we can figure out.