Here is the conversion. Just got a fresh 100# container of cal hypo and there was a big blue scoop included. 24 fluid oz --> 700 grams --> approx 1.5 pounds. Verified this with a scale too. The grams --> pounds (avdp) conversion numbers work out too. The ounce scale verified to be liquid too. So, one 16 oz cup full of the stuff is pretty close to a pound.
Al