The amount of DE that people sometimes add to their sand filters is minute and isn't enough to clog anything. The pressure with which water exits a backwash hose is impressive; we route it over a paver so it doesn't blast a hole in the lawn. As to big stuff, there won't be any big stuff in the filter medium. Big stuff is caught first by the skimmer basket and, if anything gets through, by the pump pot. At worst, you might get very small fragments of leaf bits or tree flower parts in your sand. What I see when I backwash is dirty water of a greyish brown color with tiny dark specks in it. Nothing to stop anything up.