Open the bag of bentonite. Add it the powder to the water circulating pan of the drill. Pour the powder in slowly so as not to cause lumps in the solution.
Allow the powder to circulate in the water pump and mix for at least five minutes before drilling.
Resume drilling the well when the solution is properly mixed.
While drilling, catch some of the bentonite solution in a clean container as it circulates back into the return water pan.
Allow the bentonite solution to settle for five minutes. Strain out the liquid and examine the cuttings in the bottom of the container. Too many cuttings means that the viscosity of the bentonite solution is too low. Add more powder as needed to increase the viscosity.