overwhelmed with this new tank i dont even have yet

[globaldesigns]

I wouldn't worry, especially if your sump will overflow, just make sure you have a check valve installed, then at least water can't come back down your return.

When I setup my 300gallon total tank (display and refugium) I was a little overwhelmed too. I was questioning why I did this, especially when I had the Display overflow ontop of me, because I didn't have the flow matched too well. And when I did it a second time, again on top of my head, I was really wondering why!!!!

Just take your time, all will be good. That is what I learned in this happy, time and patience.