OK, its not really my overflow... but the water leaving my overflow. It makes the occasional loud gurgling... not quite a flushing effect but VERY close. I have tweaked with the air intake at the top to no avail. I have that ribbed tubing that comes with the overflow and I am thinking of ditching that and using PVC to run a pipe to my sump. I would have the pipe submersed in my sump.

I have built a durso pipe that fits in my overflow box and it works really well... what I think it happening is the water is getting churned up too much with that ribbed tubing and causing excess air.

Does anybody have any ideas?

Keith