Originally Posted by Cottagewitch
There is a sticky thread in the lighting section about CFLs that might help.
Wow! What a great read that was!
I obviously don't have a PAR meter but based on what I've read and comparing it to my setup I would say that the light level in my tank is medium to low light. There are 2x 15w bulbs (6500K) in there, placed about 3 inches from the water surface. The fact that they are positioned horizontally rather than vertically likely reduces the amount of light that is reflected back into the tank but I think the main culprits here are the reflectors, which I will now try to replace.
Thank for pointing me to that thread Cottagewitch!
More to come.