Reefobsession
New member
Do you make these adjustments on the 400W bulb or change bulbs?
With the 400W bulb. It just dims it down to 50%. I don't thin it harms the bulb at all as long as you run it at that wattage for the day and then switch back to 400W the next day. Fluctuation of the bulb might not be wise all the time, but if you do it only a couple of times, it should be all right.