All,

I'm plumbing my 65 gallon aquarium and I installed a Durso Standpipe into the overflow chamber. The standpipe does it's job and the noise level from the aquarium is very quiet. My issue is now where the water runs into my sump. It's very noisy. I am using 1" spa flex tubing for my plumbing underneath the tank. If I put the end of the hose 2" under the water I get a horrible gurgling sound. If I place it above the water, I can hear a rushing of air into that tube.

Is this an issue of my standpipe? Or is the issue with my return plumbing? Anyone have any ideas?