So, I aws putting some finishing touches on a grwo room I was putting together, and when it came time to upgrade my bulb, I decided to take the opportunity to do a quick side by side... So Bulb number one was a 3 day old "optilume" 400 watt metal halide. I decided to step it up to a "hortilux blue" 400 MH (a 90$ difference...) just to see what would happen. And my results were not disapointing. So keeping in mind my equipment; -Galaxy 400 select-a-watt electronic ballast -Viper 6" air cooled hood -4" shit tear can fan -and of course the two bulbs... As for a light meter, I am using the titansupply PAR handheld meter. A dandy little unit if I do say so myself. so not pics right now... but the results are as follows. Optilume 400 MH- Avarage PAR 24" from reflector - 208 PAR Hortilux BLUE Avarage PAR 24" from reflector - 259 PAR sooo.... yeah, thats a 25% increase in usable light (give or take) with no exrtra cost per month in energy. !!! !!! just wantedto share that info with those who care!