I decided to drop the light down to 7hour. Only the back unit is on theres no way for me to have 1 of each tube on unfortunately, Do u think the plants at the front of the tank may not do so well? I'm having difficulty with the co2 because I keep breaking my diffusers! Just have an air stone at the moment, put it on too high and u just get huge bubbles. Waiting for 2 more diffusers.