Yes, they tell you this to try to keep you from overheating the ballast or bulb....as long as fans are involved and keeping things cool, you can run it 24/7 on, so 18 on is not a problem at all....ck the temps of the ballast, plug, cord, etc occasionally to make sure they are just warm and not hot...hot is a problem, (generally means a loose or bad wire connection) warm just means it's working right. :jointsmile:
TANKJR Reviewed by TANKJR on . More lighting questions! My 1000 watt HPS light says I can only run the light for 12 hours. I'm in the veg stage and I wanna run it for 18 hours. Can I do that even though the box says no? Rating: 5