Thanks everyone!
The sponge in the overflow is a course sponge, I plan to keep my eye on it.
We finally got the sump up and running, exactly one week after we started to cut and glue the baffles, though I've been collecting materials for ~3 months. It could of been done faster, but my boyfriend was dragging his feet lol, he was very handy over the weekend though, framing our new bathroom, working on our stairs and even making a dog door. So I can't complain lol
I do have one complaint though... The overflow box is very loud.... How can I fix this???!
We did the power outage simulation, the sump holds the water that is siphoned from the display, no problem, with some room to even spare.

the siphon remains intact, and returns to normal when the power is restored. I drilled a small hole on the return nozzle, which stopped the back flow that we encountered in the first test run, before we glued. I am concerned however about the possibility of the siphon being broke if air were to build up, or some other reason, which would cause our display tank to flood. I've heard a little about an aqua lifter pump?? I don't really know much about them besides the name, so if anyone has any info or suggestions that would give us piece of mind. (We have been remodeling- new floors, new trim, etc.... So if my tank leaks, we will have major issues.... Lol
Boyfriend threatened that if it leaks, he will move the tank to the unfinished basement...)
We still have a few things to add, bio balls, refugium plants, and other media.. We also have a check valve that will hopefully work, in the mail. (Which should help, we have our pump at the lowest setting and it's almost too much)
Also, I built an algae scrubber following the "King of DIY"'s super scrubber YouTube video. I'm excited to see how it will do. It's hard to see in my photos, it's the black lid in the refugium section.
Without further ado:
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