I'm new to the forum and a fairly new pool owner...this thing's been kicking my butt for the past 4 years now. We just switched out our very old DE filter for an EC65. Thing is, the filter has suction as it's filling up with water but, once it fills, you can see the suction decrease drastically to almost nothing. We tore it completely apart to see if there was any blockages, nothing. We turned on the pump to make sure it was pulling water in and it's all good there. Seems like it gets airlocked or something once it fills up. Any suggestions?