"( unless you bolt it to a 6 bulb t5 fixture, then there is very little shadowing!)"
That is kind of what I meant. If I have main LED in the middle, and then a "string" along the front of the tank pointing towards the bottom center and a string along the back of the tank pointing towards the bottom center, aren't the stings then performing the same function as the T5, assuming the strings are diffused enough to not function like a "laser beam"? Isn't that is why there are 90 Deg and 120 Deg optics on the main lights, so that the LED do not operate like a laser beam?
Maybe there just needs to be better "diffusing" on the LED Strings... If that diffusing isn't there, then I would agree a T5 would work better for the shadowing...
That is pretty much the story. Leds, even with good optics on them, very readily throw shadows and disco ball effects due to their small source. Until you get the light from them to be coming from a wide reflector, that is always going to be the case.
My back (t5) fixture is angled forward slightly, and the photon is angled backwards, slightly more.
I ran t5 only, then led only. I love the mix, was not satisfied with led only. T5 only was fine, except for the fluorescent pop that led can provide, was missing.