Yes LW, i agree. And i discovered a new reason that explains the low growth rate these last days. Yesturday, when i entered my grow room, i noticed that the temp was quite cool. It's generally 28° celcius, it was 22. And i was not dazzled as usaual by my 600 HPS. I was stuck, thinking, and the bulb swithed off ! Strange ! As i had put a 150 W MH and a 20 w CFL to cover more the area, i was not in the black, and the bulb switched on, and so on. The bulb is quite dead. I've got to change it, anyway. So i put a 250 w and a 400 w HPS to fix the problem and i saw that only the normal 400 w grow lux HPS was giving more light than my 600W special HPS. So i've got 2 questions :

1/ Why is my bulb already dead ? I used it far less time than the warranty tells.

2/ How long time has the bulb been giving few lumens, and what is the consequences on the yield and the finish time ?

Anybody knows ?

Fhydro