CRI is one definition of "makes the perfect daylight look"...
Of course "which daylight"..
FF is spiked in cyan so there is that.."perfect daylight look" includes a healthy proportion of it..
Water attenuation is mostly in the red for us and glass absorption is minimal and fairly even across the visible spectrum.
Tannins and junk in the water throw CRI out the window more than anything.. but I like it to go in at least.. maybe not come out..
MORE of an FYI for some than any "criticism"..
My low maintenance 40 is a good example of screwing w/ CRI.
After awhile I run the tank through Nitrate removing resin which coincidentally removes tannins..
You'd be surprised how many there really are.. and how sometimes unnoticeably they "yellow" your water..
well there are other tannin removing filter components..
Anyways really nice tank..
$100 bluefish mini and you can slide 5 channels to your hearts content..
too bad their programming is simplistic..