I'm in the middle of a 40g breeder build with a 20g long sump. I am having a lot of rattling coming from my return pump. It sits on suction cups on the bottom and it isolated with soft plumbing from the pump outlet to the hard plumbing. The pump is a AQUATOP MaxFlow swp-1300 and has a output of 343gph with zero head pressure. I have roughly 3 1/2' of head pressure so the pump puts out roughly 290gph. The pumbing from the pump is 3/4" and I am running 3/4" plumbing up 3 feet and then splits into two 1/2" return nozzles. Does anyone have any recommendations to quiet things down or should I invest in a larger pump?