I am having a peculiar problem with my watering system. I am new to raising chickens and so I read multiple ways to provide water. I got me some pvc pipes and elbow joints etc. I pushed it all together (no glue) capped the bottom end, filled up capped the top. In theory when I remove the bottom cap the pipe should hold the water in through pressure/suction/vacuum/ simple physics. My dilemma is that of the two I set up one works and other steadily loses water. I got new caps, I sanded edges to make the less lippy. What am I doing wrong? How could I fix this issue?