I thought the bulbs were coming with the fixture. If the ballast is M57 (unlikely) It would be better to go with XM's as they are supposed to work well with M57 ballasts. I myself use Aqualine 10000K' s which actually test out at 14000K. I get mine from Premium Aquatics. I have had good success with them. I always get my stuff shipped by way of the USPS. No hassle with customs. I always pay just GST and the $5.00 handling charge.
