I finally have everything pretty much finished up so I filled the tank and sump to test everything out before adding my good water.
I left some room in my sump and filled the tank just above the overflow box. I tried a for a couple hours last night to get the water to start siphoning out of the tank but was unsuccessful.
What do I need to do?
Here's whats my External overflow box's look like-
Mine is a little different with 2 "U" tubes going to a center chamber where it overflows into 2 outs. But the same concept.
Here's an actual photo of mine (the internal specimen box is not attached in the photo but I do have one).-