While I had the covers off of the 40 watt Coherent surgical laser, we read the specs on the coolant pump.(laser units manufactured in Hull, England, with a Japanese coolant pump no less)

The coolant appears to be water with typical ethylene glycol, (antifreeze),

The coolant pump shows 3 numbers for flow, indicating three conditions....(lots of specs for medical equipment)
"MAX FLOW 11/12/11" liters per minute (1 liter ball parks with 1 quart, so 3 gallons per minute, just approximate)and "HEAD 1.5/2.1/1.5 m" , taken to be "m" for meters.

so, different output for the laser and different units, with unknown coolant (until I get documentation)

but at least it is something to compare with for a commercial unit, once you break out the calculator.