Using an $96 Hortilux with added blue 400HPS on one side, and a $129Hortilux Ultra ace Conversion bulb (off a 400HPS convertable ballast) I found the conversion bulb gave better results it terms of bud density and overall growth and consistency of canopy height.

Perhaps it would make a difference if you are using the one bulb for both veg and flower.

If I had to purchase again I would not have spent the extra $$ on the added blue to use for flower only.
blink_inc Reviewed by blink_inc on . which bulb is superior which of these bulbs are better Grolux 400w Dual Spectrum Sunmaster 400w Son T Plus Rating: 5