I posted a while back about some pump troubles. I managed to install the new pump motor without trouble; the fourth or fifth time I fit everything back together and it's worked a treat since. However, in the last few days, the pump has developed a bit of a clattering sound that goes away entirely if I apply downward force to the PVC pipe coming out of the top of the pump housing. Do you think it's a noise I ought to worry about, or attempt to fix? My pump sits on a concrete pad, if that matters. Thanks for your help.