so i just opened the pool today to a green swamp. i put 8lbs of shock and 14oz of back up 2. ive cleaned the filter (pentair FNS plus) and also backwashed it a few times. im getting around 30-40psi and after roughly 30 sec my skimmers stop working and i get a huge burp of water/bubbles push out of my main drain in the deep end at the same time. when i put it in recirculate mode, the skimmers work fine. any idea what would cause this? i’d call my local pool store but they’re so backed up it will probably be weeks before they can get to me. please help! will answer any questions to help solve this that i can. thanks in advance!