My pool was running fine for the past two days. Then the returns(jets) in the shallow end subsided. I cleaned out the skimmer basket and pumps basket as usual and back washed. After several times of backwashing, that the pressure gauge on the DE filter still read 30. So I opened the DE filter and cleaned it. I also cleaned out the jandy filter which was clogged with really old DE. When I tried to run the system again, the pressure was back to 30. And now there was a flow from both jets in the pool. Where do I begin with trouble shooting?