[samuraistuart]

Parks 50, as we know is a "fast" oil, has a nickel ball speed of 7 seconds.
AAA has a nickel ball speed of 9-11 seconds.
Quench K has a nickel ball speed of 7-9 seconds.
Canola oil at 130?f is said to have a speed of around 9 seconds.

I can't seem to find any info giving nickel ball speed of water or brine.

I did find a chart that showed that a 10% brine solution has twice the cooling rate of water.

I figured I should edit this to add to that comment about brine/water.....I don't think that brine is actually TWICE as fast as water, but that the salt helps to break down the vapor jacket.....so in essence you get a faster quench rate.