I made a call on the lighting...
Current USA 36" TrueLumen Pro in 8,000K
The tank mounting brackets raise the light about 1.5"
Based on the PAR data contained in samamorgan's LED PAR thread
, a single unit at 23W should provide ~75 PAR. I expect the actual PAR numbers to be slightly higher than reported as the PAR measurements used were from tests conducted by AquaNerd using the marine version of the light. The Apogee MQ-200 PAR meter underestimates PAR when measuring very blue light by up to ~20%. I'll share PAR data once set up.
This should provide enough PAR and a very small footprint resulting in minimum distraction. The only think it doesn't provide is moonlighting, but that can be addressed separately.