First time opening pool. Tried to pay attention to what PB did when closing for season last year. I have removed all the plugs in the returns and skimmer and put the filter back together but when I opened the valve no water enters the system. I've tried the valve in every position I can think of and no water ever enters. See pictures attached. What am I doing wrong? Really wanting to get water flowing so can make sure any of the chilly temps expected overnight do not cause any issues.