Plumbing question ?

[reefmandan]

I may consider using a Durso for your main siphon drain. The reason is, you will have stagnance at the bottom of the overflow. Using a Durso will create flow in the bottom, and all you need to fo it place a siphon break at the top (assuming your sump cannot handle the volume of your overflow. Secondly, I would use the emergency as a trickle, since protein will build up on the surface of your overflow otherwise.