The above answer is a good one, but you might also check the depth of the water in the well. If it seems deep enough, you might shorten the pipe into the well by about a foot. The extra large pump may just be stirring up the sand that is always present in the bottom of the well. By shortening the pipe, you would keep the pump from pulling water directly off the bottom of the well, and therefore not get the sand. Before shortening though, make sure you will still have enough water standing above the foot valve to meet your needs.(posted 9012 days ago)Sometimes sand just caves into wells from the vein of sand your water is coming from. Extra sand in the water may be caused by that and it might just be a coincidence that it happened when you got your new pump. Depends on how long ago you installed your new pump.
Our well has powdered lignite coal in the bottom of it. Sometimes we pick it up with the pump or even with the well bucket.