I dont think cool water is a bad thing for your plants as long as your air temp is around 75 to 80 degrees farenheit. As far as lighting goes, I would probably reccomend 24/7 lighting for the first two weeks for new sprouts, then you can go 18/6 for the vegetative phase (roughly another 2 weeks), Then you switch to 12/12 for flowering (up to 3 weeks). Just my 2 cents.