Foam output question.

[red fescue]

Foam generation question:
Water + detergent ( mixed at 2 cups per 5 gal)

Today's results - pump delivering 1.5 gpm generated 9 gallons of foam@ 98gm/ liter. This was a 60 second test.

Is this the normal range of output?
How many gallons of foam would 5 gallons of water and detergent create?