My filter trap is not holding water. Every time I have to start up the filter I have to open the trap and let water in to start the filter anyone know why??? Now this morning the o ring broke and water is everywhere and I was rushing out to buy a new o ring...not a good pool morning. Am I doing something wrong? I am a new pool owner and have read all the manuals and thought I understood the trap should always have water in it to run the filter please help