I forgot to mention that in http://www.personal.psu.edu/faculty/...omparison.html Sanjays ballast test,
The 400w Blueline E-ballast beats the 400w HQI ballast in PPFD on Ushio bulbs. So forget about conventional magnetic ballasts, but E-ballast may or may not be less bright than HQI. You decide.
</html>
Bookmarks