hello, i've had this inground pool for 18 yrs and never had this problem. after vacuuming the pool i switched to filter the pool and now the pump won't suck enough water into it to build up pressure. i noticed that there isn't any suction over by the skimmer. i thinking of trying to blow out the skimmer with some air pressure but saw something on this site about using a hose with a rag to try to clear it? how does this work and why use the rag? thanks for any help. Randy