Good post Stephen - that's the same formula we used to use when I studied (and passed) for my DipTech in Instrumentation and Controls in the 80's.

And representative of my experience too, although, as I have stated, in practice, I see very little to no appreciable improvement in temps running pumps at 4.3 LPM vs 7.5 LPM - this as measured by the Koolance flowmeter, flows might not be 100% accurate, but for the purposes of the experiment, close enough....