Starting from left to right:
On the far left we have what will soon be a Chaetomorfa reactor, then a filter sock where the outlet from my HOB overflow box is. Below the sock I will have some bio-balls. Inside the pile of bio-balls is a pump that pushes water to a custom build reactor manifold. On the right side of the sump I will put my protein skimmer as well as a return pump back into the tank. On the furthest right there are 2 more reactors (GFO and Activated carbon are what I chose for those).
Funny side-note here: I actually added a piece of acrylic to pull the filter sock up some out of the sump so it isn't touching where the bio-balls will be
Since the sump is relatively small compared to the tank (15 gal sump on a 55gal tank) I chose to add 3 reactors to get a little more water volume. I haven't glued any of this yet (or painted it!) so I am still willing to make a few adjustments to the setup.
Here is what the plumbing looks like on the back of the tank:
What do you guys think? I came up with this design after a TON of research and probably hundreds of hours of youtube videos all giving different suggestions! I currently have the tank on this canister filter and it is a pain to keep my parameters up with it.
I would have documented the build process but it has been a couple weeks of trial and error with different ideas before I finally landed on one that I like.