At 350mA, the specified difference is 7 - 14%. That is, the Q4 is 100 - 107 lumens, and the Q5 is 107 - 114 lumens. So, on average, 7%, but maximum 14% difference. At 700 - 1000 mA, there aren't published ranges for each bin, but you can extrapolate upwards from there (minus a few percent due to lower efficiency at higher current, I'm sure.)
Also keep in mind that one thing we are nearly ignoring in this thread is the color bin applied to each batch of LEDs that Cree manufacture. We are typically using the "cool white" product, which can be broken into 14 or so different color bins! The difference between one extreme and another can be pretty large.
Unfortunately, most vendors focus on the brightness bin and don't provide us with the color bin, though some do provide an order code (part of the model number) which can be interpreted into a range of color bins. Luckily, the few times I've gotten cool white XR-E LEDs from the usual sources, they've all been in pretty mild, neutral color bins near the middle of the spectrum (WG, WC, some WM). The differences between these common bins can be interpreted as a few hundred K, so it won't make a huge difference. Most of these bins are right around 6500k. However, if you ended up with a WK bin, it would make a very large impact - this bin can stretch to around 10kk, and is at the more purple end of that range, so it'll look more significant paired with royal blue LEDs.
I think it's also important to consider that some people in this thread who are running a 50/50 split of cool white and royal blue are running the whites at 1000mA and the blues at 700mA, which will make a very large difference. In fact, going back to the origin, that's what Soundwave was running.
Another consideration is purely the way we observe colors and talk about them in the reefkeeping hobby. The concept of degrees kelvin indicating a particular color is a pretty weak concept, and gets worse "off center." So if you have a color bin of LED that's above or below the BBL, it's no wonder you are struggling to describe it in reefkeeping terms.
Extending that train of thought, LEDs are far more pure light sources than anything else we use in the hobby. White MH and fluorescent bulbs tend to produce very spiky light in terms of wavelength, whereas LEDs tend to produce a very clean curve that has a nice hump right at a designed location. Hence, though an LED array and an MH rig might appear to produce similar color light to the naked eye in experimental conditions, once you put them over a tank, the appearance of the tank might vary significantly.
So, yeah, turn down your blues a bit and you'll get something whiter.
utput.
