Setting up external overflow box

[dreamcatcherr9]

I attached three (3) examples. For the standpipes in a Herbie or Bean Animal style set up.

Emergency is left completely open and unobstructed. But primary and secondary I see a few different methods. Does it matter?

I have seen example of left open, covered with strainer and connected with PVC elbows to “U” back down.

Will any work, just a preference?

 

[lapin]

https://www.reef2reef.com/threads/setting-up-external-overflow-box.710990/

 

[Water Dog]

I like elbows, they make it quieter. Also not a fan of the the valve type or its position shown in your upper Herbie picture. On the primary full siphon, it should be gate a valve. Second, the gate valve on the primary full siphon should be as close to the sump as possible as it makes it easier for all the air to purge out of the full siphon drain upon startup. Another tip... that primary drain into the sump should extend no more than an inch beneath the surface of the water where it enters the sump. Again, this makes it easier for air to purge from the full siphon upon startup.