Can't say for sure! Yet I can tell you I have used Ushio / XM / and cheap knock offs like the sale ones you described. XM 10,000K 250 watt have the light I like the best (asthetically). Yet 2 out of 4 bulbs burned out within a week. They replaced them but it was a pain. The cheap bulbs I started with are still working and I keep them for back up, but my corals didn't grow as well with them as the do with the XM or Ushio. Also colr on cheaper bulbs has always been much bluer than like rated more expensive bulbs.