I had a mag7 acting as the return pump from the refugium/sump to the display. Flow was decent, sound was loud but manageable but definitely not dead silent. I wanted to add a chiller, UV and phosphate reactor without adding additional pumps. So to do it, I upgraded the 70watt 700GPH to an Eheim 1262 at 80watts 900GPH. I also didn't want the heat load to increase. Now with the 1262 as the return with a T pumping to the main display return and feeding the chiller (suggested at 300-600GPH) which then outputs to the UV then the output from the UV is split with another T going into the sump and phosphate reactor. Problem here is that the Eheim is too efficient, flow to the return is crazy fast the built-in kinda durso is constantly gurgling and making sucking sounds. Second issue, my sock is no longer able to handle the volume of water is now allowing micro bubbles from the drain to get back into the return. Will changing the factory return pipe to a true durso fix the gurgle? With the microbubbles, I was looking at splitting the drain into two filter socks which should keep the bubbles from going to the return pump. Anyone have other suggestions?