20 gallon long tank
4 pieces of glass cut at lowes, dimensions I forget you'd have to measure the tank
aquarium silicon I had laying around
10 dollar clip on work light from walmart
60 watt bulb from the lamp where the tank is currently located
Basically, the return section only needs to be the length of your return pump. This is your third section. You will place three dividers between it and the second section, it is best to see a picture rather than me trying to explain it...
http://farm3.static.flickr.com/2300/2367447542_502268dc86_o.jpg
Then you just have one piece of glass between the first and second sections.
The only tricky part is the middle piece dividing the second and third sections. I used old magazines to hold it up while I applied the silicon and used painter's tape to loosely hold it in place.
When applying the silicon, you want to make sure that you do so smoothly. Cut the nozzle at a 45 degree angle, it helps. Don't gob it on, just run it the entire way up the side. Use a popsicle stick to smooth out any bubbles. And fyi, you don't want to get this crap on your hands. If you are unsure of yourself or messy...wear gloves.