Gunnie u said " That is where most of your bacteria will be - in your filter." What do u mean by that? Are the filters that we use have bacteria in them?? If so what should be the procedure when you are replacing a filter (I assume replacing filters every 4 weeks is a normal procedure) !!!Gunnie said:Yes, definitely get your filters running while your tank is cycling. That is where most of your bacteria will be - in your filter. I don't think the lights have anything to do with your fishliess cycle, and your tank lights can be turned on. Do you have live plants in the cycling tank? If so, I'd say to go ahead and use the lights you want now.