I was reading my service email today and noted that my pool guy added DE Powder 1 Pound. Is this common? I have a sand filter. I intend to call him on this tomorrow if there is no good reason. I'm just impatient and want to know now - at 9:00PM. And also.... I intend to start servicing my pool on my own but haven't gotten around to it yet. I bought the kit sold on this site and the spinner.