Here's an interesting question. I am living in a 220v 50hz country. My lights/timers are from the states 110v 60hz. I already know my timer is loses 10 min an hour (about two hours a day). I periodically adjust the timer to display the current time. I will ALWAYS adjust it twice a day; but usually I adjust it four or five times a day. Point being, at worst my grow room may stay illuminated 15-20 min longer than programmed and off for 15-20 min longer than programmed. I figure as long as the inaccuracy is proportional (light to dark) I should have no problems. My light to dark time stays the same...just shifted However, i didn't consider the actual lights. Does anyone know if a ballast designed for 60hz but run on 50hz will suffer negative effects? It seems to me I may not be getting full power. OR Will my lights just draw more current? The lights seems to work just fine, but then again I've never grown before...so I wouldn't really know. Any thoughts?