A little Fiber Clear goes a long way. A traditional D.E. scoop (the old orange or blue handle) equals ½ pound of Diatomaceous Earth. We measure Fiber Clear not by weight, but by volume. Use of Fiber Clear is approximately 1:8 of D.E.. Included with each 3 lb., 7 lb. and 25 lb. bag of Fiber Clear is a 16 oz. beverage cup, as measured by volume. Instructions on the back of each bag indicate the proper amount of Fiber Clear to use in your DE filter, based on the square feet of filtration area.  These instructions are also posted on the website. Consult the factory with specific questions.