It appears to be the same thing as the Aqualuminator.

I did a google search on "Darkbuster replacement bulb" and "Aqualuminator replacement bulb".

http://www.poolstore.com/store1/welc...tor/index.html
https://poolgear.com/index.asp?PageA...RODGROUP&ID=79
http://search.ebay.com/aqualuminator

Hope that helps.