Hello Reef2Reef Members... I'm new to the forum community but have been monitoring all your posts for a long time... I've had a reef tank in the past.. got out of the hobby and am now making a comeback... I'm setting up an oceanic tech 120 reef and just got all the plumbing done. I filled with tap water to check for leaks and testing things out before i fill with saltwater and rock... so yesterday i turned the pump on and noticed my overflows were surging and a lot of air in the return lines making so much noise... im using the megaflow by aga... i've ran this system before and never have had this problem.. my last system was super quiet.. I have a fluval sp4 return pump and its powering 2 BRS Delux reactors with a gate valve on each and a gate valve regulating the flow to the returns.. I tried turning it way low and it is still so loud... the bubbles in the sump and return hoses are gurgling like crazy it sounds like i'm running 10 dishwashers and 10 washers at the same time... is there anything i can do to fix this issue???