Hey, there!

My overflow box uses a Durso pipe to siphon water down to the sump. It's gotten into the annoying habit of breaking the siphon at irregular intervals. Once the siphon is broken, the overflow fills back up, and the siphon restarts itself. However, it's quite noisy when this happens, and I'm concerned about long-term complications. The return pump is not yet a year old (sorry, not sure of the make/model). I removed the return pump and ran it in hot water with vinegar for a few minutes this evening. That seemed to improve the output from the pump a bit, but the siphon in the overflow is still breaking randomly.

Any ideas?
Derry