I have been getting first stones, now gravel in the sump pump crock. After vaccuuming them out, they happen again. What would be the reason for this, and how do I get it fixed? They plug up the bottom of the sump pump. Also, whereabouts in the pipe does the check valve go? I'm a woman, so please write so I can understand it. Another question - how do you hook up a 2nd pump? I have lived here 40 years and my basement has been flooded many, many, many times. I am so tired of it. Thanks, Ruth Ann