alison, I run 2-atinic URI and 2-50/50's URI right now. but I am getting new bulbs because these have been burning for 8 months. The new set will be 1-50/50's and 2-atinic and 1-aquasun. I am getting a new shipment of stonies in and they need a warmer bulb. They need more red light. not so much...