Step 1: Cutting Project Box

The first thing to do is cut out holes for the heating elements, temperature controller face and thermometer, and the cable holes for the water pump and main power. I used a 1 3/8" "hole saw" (drill bit) to cut perfect holes. I then used the rotary tool to cut out the square for the temperature controller face. You can use a drill for the rest, matching the drill bit size to the holes you need for the other elements and mount.

Step 2: Wiring It All Together

Using the holes you just cut/drilled, insert the components into their appropriate places. The STC1000 has orange clips to hold it in place and keep pressure against the wall it is sitting in. Cables for the water pump and thermometer should be hot glued into place.

I learned a lot in this project regarding electricity. To be honest, I should not have attempted this project without better training. I cut my teeth on this project, and I am the first to admit that it was dangerous and dumb.
The most important thing to be considerate of is that the gauge of wiring you are using can withstand the amount of current you are pulling. The heating elements are going to pull 16.6 amps. Wiring them in parallel doubles that, in series it halves it. I am wiring them in series since I can afford to being that I am using two elements.

I cut the replacement cord into two parts. The first will be what protrudes from the box and plugs into the wall. The second I will pull the separate cords out of to wire up the pieces within the box.

Since we are also going to wire in the water pump, we need to cut that wire at whatever length we want to be able to extend from the box (and then some). Mark which side of the cable is positive (it will be the side where the plug is smaller than the other one). If neither is smaller, then it doesn't matter which side is which.

Right off of the main cable I split the neutral and positive wires. The positive wire is coupled with other wires via a wire nut (one to the AC in of the temperature controller, another to the heat input of the temperature controller, and the last to on of the connections on one of the heater elements, and one to the positive end of water pump). The neutral wire will go into a wire nut with several other wires as well (one to the AC out of the temperature controller, one to the neutral end of the water pump, one to the neutral side of the once wall outlet)