nanotuners does sell the OEM ballast (a hella lot cheaper than the petsolutions link), but they seem to pop more frequently than the fulham ballasts....
i had a biocube 8 that popped the ballast 3 times....i had the local rep's email address & he'd always send me a free replacement along w/ a ups sticker to return the defective one, but it was just a pain in the arse to deal w/