Hi Me and a friend are building plywood tanks and hoods. I have put some of the drawings of my hood on the page below. I would like some comments on how to mix different tubes to get best growth. Using 3 week timers I will be able to simulate very sunny days and cloudy days. I will also be able to simulate sunrise and sunset. http://www.roka.se/maf/articles/tankhood1.html TIA KrA