I have two of the fixtures in the photograph mounted above a double vanity. I installed a dimmer switch since the six bulbs are way too bright no matter what time of day. Dimmer switch dims fine but the lights flash brightly when you first turn them on, then they steadily flicker/pulsate when dimmed. I thought it might be something with the total wattage of the six bulbs... I took out one bulb from each fixture and it improved slightly at first but one day later, back to flash and flicker. How can I get the dimmer to work correctly with these fixtures and bulbs?